In the New Zealand telecommunications landscape, SMS Short Codes are the gold standard for business-to-consumer communication. These are 3 to 6-digit phone numbers specifically provisioned for high-volume, automated messaging (A2P). Unlike standard mobile numbers (long codes), short codes are designed for reliability, brand recognition, and compliance with local carrier requirements.
Do Businesses Need Their Own Short Code?
No. Many customers use a built-in code successfully.
On the Starter plan without a short code, when you send a message we analyse the message content and send it on an approved short code dedicated to that type of message.
When a mobile receives a message from you, they have a five-day window to reply. Sending another outbound message to the same mobile resets the timer.
After the 5-day window, an unmatched reply on a built-in (shared) Short Code is dropped. On a dedicated number it's routed using the number's default inbound settings. See Setting the Sender on SMS Messages for the full breakdown.
Using the built-in Short Codes work well for:
- Appointment reminders
- Service alerts and notifications
- Customer support replies
- Internal team communications
- Two-factor authentication (2FA)
When do you need a dedicated Short Code?
- Wanting customers to text you first (inbound-initiated conversations)
- Running regular SMS marketing campaigns
- Building brand recognition around a specific number
- Running competitions or keyword campaigns (e.g. "Text WIN to 4567")
- Sending high volumes where a consistent sender identity matters
Short Codes vs. Long Codes: Why New Zealand is Different
While some international markets allow business messaging via standard mobile numbers, New Zealand carriers heavily regulate these channels. Using a short code provides several distinct advantages:
- Superior Deliverability: Short codes are pre-approved by NZ carriers (Spark, One NZ, 2degrees), meaning they bypass many of the aggressive spam filters that often block long-code traffic.
- High-Volume Throughput: Built for scale, short codes can send thousands of messages per minute, making them essential for time-sensitive alerts or large marketing blasts.
- Consumer Trust: A dedicated short code (e.g. 8888) acts as a verified brand identity. Customers are significantly more likely to engage with a 4-digit code than an unknown 10-digit mobile number.
- Compliance: In New Zealand, alphanumeric headers (sending from a "Name" instead of a number) are not supported. Short codes enable the 2-way communication required for legal opt-outs.
⚠️ You can't use your own mobile number!
New Zealand mobile networks work with the Department of Internal Affairs to actively flag business SMS sent from standard 021/022/027 numbers. This is to keep the channel trustworthy and prevent the kind of spam that other countries struggle with. TNZ provides a compliant Short Code on signup so you don't have to wait or apply for one yourself.
Types of SMS Short Codes in New Zealand
Included
Built-in code
Included
Best for alerts, reminders, 2FA, and conversations that begin with an outbound message.
- Available immediately
- Five-day reply window
- Promotional messaging not supported
Best Value
Dedicated 6-digit
$89 / month
$299 one-off setup
NZD plus GST
Best for customer-initiated messaging, keyword campaigns, and promotional messaging.
- One number assigned to your account
- Inbound messaging at any time
- Unlimited keyword campaigns
Shortest Number
Dedicated 4-digit
$299 / month
$599 one-off setup
NZD plus GST
Best for the same dedicated use cases when having the shortest available number is a priority.
- One number assigned to your account
- Inbound messaging at any time
- Unlimited keyword campaigns
Feature comparison
| Feature |
Built-in short code |
Dedicated 6-digit code |
Dedicated 4-digit code |
| Number assignment |
TNZ selects a built-in code for each message depending on your use-case |
One 6-digit code assigned to your account |
One 4-digit code assigned to your account |
| Inbound messaging |
Send outbound message first to capture reply back |
Customers can text the code at any time |
Customers can text the code at any time |
| Keyword campaigns |
Not included |
Included (unlimited) |
Included (unlimited) |
| Promotional messaging |
Not supported |
Supported with a Free-to-Text code |
Supported with a Free-to-Text code |
| Provisioning time |
Available immediately |
Approximately four weeks |
Approximately four weeks |
| Setup fee |
Included |
$299 (NZD ex GST) |
$599 (NZD ex GST) |
| Monthly fee |
Included |
$89 (NZD ex GST) |
$299 (NZD ex GST) |
| Message fee |
Your normal SMS price |
Your normal SMS price |
Your normal SMS price |
- Setup Time includes mobile networks reviewing and approving your short code's use case and provisioning the code.
Short Code Reply Cost
Mobiles pay to send to your short code, or you can choose to absorb their message cost.
| Feature |
Standard Rate Short Code |
Free-to-Text (Zero-Rated) |
| Cost to Mobile |
20c per sent message (typically), billed to their mobile account |
$0.00 (Free) |
| Cost to TNZ Client |
Setup, monthly and outbound message cost.
No cost for receiving inbound messages. |
Setup, monthly, outbound and inbound message cost (business pays to receive). |
| Best Use Case |
2FA, Reminders, Internal Alerts |
Marketing, Competitions, Customer Support |
| Cost Instruction |
If the mobile is required to send to the short code, instructions must state "Standard charges apply" or "Replies cost 20c" |
No requirement to explain costs (although "free reply" improves response rates). Must still comply with Spam Act regulations (including an unsubscribe instruction such as "Reply STOP to OptOut") |
- Message Cost is an indication based on the Starter Plan fees (NZD ex GST) and references a single SMS Part.
Can I choose my Short Code Number?
Yes. You can likely choose your preferred 6-digit number. Get in touch with the TNZ team if you have a specific number in mind.
Generally, "Standard Rate" short codes begin with a 4xxxxx number, and "Free-to-Text" short codes begin with an 8xxxxx number.
Can I also receive voice calls on my Short Code?
No. NZ Short Codes are SMS-only. If you need both SMS and voice for the same business, use a Short Code for SMS plus a separate landline (or mobile) for voice. See Why You Can't Use One NZ Number for Both SMS and Voice for the full explanation and the recommended setup.
Opt-Out Functionality
Under the Unsolicited Electronic Messages Act 2007, every commercial SMS sent in New Zealand must include a functional, easy-to-use unsubscribe facility. Short codes facilitate this perfectly:
- Automated Opt-outs: TNZ’s platform automatically handles "STOP" keywords, ensuring you never accidentally message an unsubscribed contact.
- Legal Requirements: Marketing messages must be free for the user to opt-out. This is why NZ businesses require Free-to-Text codes for promotional messages.
Set-Up Requirements
Provisioning a dedicated Short Code involves applications to all three NZ carriers (Spark, One NZ, 2degrees) and technical integration with the TNZ platform. We manage all of it on your behalf:
- Carrier applications and compliance paperwork
- Technical integration and dashboard configuration
- Ongoing support and compliance management
How to Decide
Start with a shared Short Code if you are:
- Sending reminders, alerts, or notifications
- Just getting started with SMS
- Budget-conscious and don't need consistent brand recognition
Upgrade to a dedicated Short Code if you are:
- Running regular marketing campaigns where brand recognition matters
- Running "Text KEYWORD to 4567" style promotions
- Wanting customers to initiate conversations with you
Not sure? Contact our team for a recommendation based on your use case, or book a dashboard demo. For details on how the Sender ID is configured at the account or user level, see Setting the Sender ID on SMS Messages.