Email deliverability in Australia and New Zealand: A marketer's guide

Email marketing in Australia and New Zealand (ANZ) operates in ways that are distinct from other regions. Unlike larger global markets where marketers often focus on Gmail or Microsoft email trends, the ANZ region has its own mix of regulations, mailbox provider behaviors, customer expectations, and engagement patterns that directly influence deliverability outcomes.

For marketers expanding into Australia and New Zealand who are trying to improve inbox placement, understanding the regional email landscape is becoming increasingly important. Deliverability in ANZ is about building trust with both mailbox providers and recipients in markets where consumers are highly privacy-aware and regulators actively enforce compliance.

In this guide, we’ll break down:

• The Australian and New Zealand email ecosystem and regulations
• Local mailbox provider presence and mailbox filtering behavior
• Common deliverability challenges

Understanding the ANZ email ecosystem and regulations

Australia and New Zealand are highly mature digital markets with strong email adoption and mobile engagement. While Gmail and Microsoft inboxes make up a large percentage of recipient domains, marketers across ANZ still commonly send to:

• Outlook, Hotmail, Yahoo, Apple Mail users, Corporate domains
• Local mailbox provider-based inboxes such as BigPond, OptusNet, iiNet, and Xtra

One major difference in ANZ compared to larger markets is that engagement quality often matters more than pure sending scale. Mailbox providers increasingly monitor opens and clicks, complaint rates, deletes without reading, spam folder actions, long-term recipient engagement. This means aggressive batch and blast strategies can quickly damage sender reputation even when technically compliant.

Australia’s Spam Act: What marketers need to know

Australia’s anti-spam legislation is governed by the Australian Communications and Media Authority under the Australian Spam Act 2003. The law applies to commercial electronic messages sent from or accessed within Australia.

At a high level, marketers must follow three core rules:

1. Consent

You must have consent before sending marketing emails. This can be express consent (the user explicitly opted in) or inferred consent (an existing business relationship exists). Pre-checked boxes, unclear signup language, or purchased lists create significant compliance and deliverability risks.

2. Identification

Emails must clearly identify the business sending the email, contact information, brand transparency. Hidden identities or misleading sender information can trigger both compliance and filtering issues.

3. Functional unsubscribe

Every marketing email must contain a functional unsubscribe mechanism that works for at least 30 days, is easy to use, and is processed promptly. In practice, mailbox providers now evaluate unsubscribe behavior as part of sender reputation. If recipients cannot easily opt out, they are more likely to hit “Report Spam” instead.

New Zealand’s Unsolicited Electronic Messages Act

New Zealand operates under the Unsolicited Electronic Messages Act 2007, enforced by the Department of Internal Affairs.

The legislation closely mirrors Australia’s framework and focuses on consent, sender identification, and unsubscribe functionality. For marketers operating across both countries, maintaining one unified ANZ compliance framework is usually the most effective approach. However, compliance alone does not guarantee inbox placement. A sender can technically comply with all the regulations and still experience:

• Spam foldering
• Bulk filtering
• Reputation degradation
• Throttling
• Temporary blocks

Local mailbox provider presence in Australia and New Zealand

While Gmail and Microsoft dominate inbox share across Australia and New Zealand, local providers and telecom providers still play an important role especially for older consumers, government sectors, and long-established residential email accounts.

In Australia, marketers may still encounter domains associated with:

• BigPond / Telstra
• OptusNet
• iiNet
• Internode
• TPG

In New Zealand, mailbox traffic can still include:

• Xtra
• Spark
• Vodafone NZ legacy domains

Although these providers represent a smaller percentage of total volume today, they can behave differently from larger global mailbox providers. Some local providers use more aggressive connection throttling, reputation-based filtering, legacy spam filtering systems, and lower tolerance for sudden volume spikes. This means senders with inconsistent sending patterns may notice delayed delivery, temporary deferrals, increased bulk folder placement, sporadic blocking behavior.

Reputation still matters with local mailbox providers: One important thing marketers often overlook is that smaller providers may rely more heavily on IP reputation than advanced engagement-based machine learning models. In practical terms, this means:

• Poor infrastructure reputation can have a bigger impact
• Authentication issues are noticed quickly
• High bounce rates can trigger filtering faster
• Complaint spikes may result in temporary blocks sooner than expected

Because these mailbox providers process lower email volumes overall, abnormal traffic patterns can stand out more noticeably compared to Gmail or Microsoft ecosystems.

ANZ telecom providers and legacy domains: Many consumers in Australia and New Zealand have retained mailbox provider-issued email addresses for years, sometimes decades. It is still common to see long-term customer databases containing:

• @bigpond.com
• @optusnet.com.au
• @xtra.co.nz

These recipients are often highly engaged if the relationship is strong, but they may also be:

• Less tolerant of irrelevant email
• More likely to manually mark messages as spam
• More sensitive to sudden increases in frequency

Common deliverability challenges in ANZ

• Smaller audience sizes: Compared to North America or Europe, ANZ databases are often smaller. As a result complaint spikes are more noticeable, engagement drops impact reputation faster, poor segmentation becomes more visible. Even a few thousand disengaged recipients can influence overall performance.
• Shared infrastructure risks: Brands using shared IP environments may occasionally experience reputation instability caused by neighboring senders. This becomes especially important during Black Friday, EOY campaigns, holiday promotions, large retail periods. Consistent monitoring is essential.
• Overreliance on global strategies: What works in the US market may not always work in ANZ. Australian and New Zealand audiences are often more responsive to relevant messaging, controlled frequency, clear consent and personalized communication. Aggressive promotional strategies can increase complaints and disengagement quickly.

Best practices for strong inbox placement in ANZ

• Prioritize engagement over list size: A smaller engaged audience will almost always outperform a larger disengaged database. Focus on active recipients, recent engagement, clear consent, removing inactive users regularly.
• Warm infrastructure gradually: When launching new domains, subdomains, or dedicated IPs, increase volume slowly, maintain consistent patterns and prioritize engaged users first.
• Monitor complaints closely: Spam complaints remain one of the strongest negative reputation signals. Reduce complaints by setting clear expectations at signup, avoiding misleading subject lines, making unsubscribe easy, and sending relevant content.
• Authenticate everything: Ensure SPF, DKIM, and DMARC are fully implemented and aligned. Authentication helps build sender trust, reduce spoofing risk, improve long-term reputation stability
• Use engagement based sending: Modern deliverability strategies should focus on engagement segmentation, sunset policies, frequency optimization and lifecycle targeting. Not every recipient should receive every campaign.

Final thoughts

Email deliverability in ANZ is evolving quickly. Mailbox providers are becoming more sophisticated, consumers are more selective, and regulators continue to raise expectations around transparency and consent. The brands seeing the strongest inbox placement today are not necessarily the ones sending the most emails, they are the ones building the most trust.

For marketers operating in Australia and New Zealand, long-term deliverability success comes down to a few fundamentals:

• Respect user consent
• Send relevant content
• Monitor engagement carefully
• Maintain strong technical foundations
• Treat deliverability as an ongoing strategy, not a one-time setup

If you are looking to refine your inbox performance across Australia and New Zealand, Braze can assist in establishing sender credibility and securing consistent placement. Reach out to our specialist email deliverability team today. Braze Email Deliverability Services are here to lend a helping hand. For more information, check out our additional resources, like our blog, previous webinars, lessons, and our Master Email Deliverability learning path.

Disclaimer: This post is for informational purposes and does not constitute legal advice. Please seek independent legal advice regarding your email marketing activities.