[1] Numerous complex dialling instructions appeared in the front of telephone books explaining the number sequences needed to reach subscribers in local "free calling" areas, and in a few cases for short-distance toll calls (usually to the local city or town), which were recorded on manually read metres in some step-by-step local exchanges.

Subscriber toll dialling (STD) was introduced in the New Zealand telephone network in the mid-to-late 1970s, a result of the introduction of NEC crossbar-based toll exchanges and their ability to perform number translation.

The original STD codes were numbered roughly south to north, with a few exceptions.

With the introduction of NEC stored program control exchanges in the New Zealand telephone network during the 1980s, and the rapid growth in demand, the breakup of the New Zealand Post Office and the creation of Telecom, local telephone numbers were standardised to seven digits.

The justification for doing so was the introduction of a directory service computer system that gave access to current New Zealand telephone number listings, not just those printed in the telephone book, and the need for a separate user pays revenue stream for Telecom Directory Services, which was separate to the 5 regional (local) telephone companies, TNI and Telecom Mobile that Telecom had split itself into, as part of the sale of Telecom and deregulation of New Zealand telecommunications services.

Since 1993, land-line telephone numbers in New Zealand consist of a single-digit area code and a seven-digit local number, of which the first three digits generally specify the exchange and the final four specify the subscriber's unique line at that exchange.

New Zealand landline phone numbers have a total of eight digits, excluding the leading 0: a one-digit area code, and a seven-digit phone number (e.g. 09 700 1234), beginning with a digit between 2 and 9 (but excluding 900, 911, and 999 due to misdial guards).

The combined domestic trunk prefix[3] and area codes are:[4] Telephone numbers for mobile phones begin with 02, followed by seven to nine digits (usually eight).

As of September 2019[update], this service will work for Vodafone and Spark Active.

The "1" codes are used for local services, including activating exchange features.