It has changed many times, the most recent major reorganisation by the Australian Communications and Media Authority taking place between 1994 and 1998.

[1] For landline telephony, Australia is geographically divided into four areas, three of which cover more than one state or territory.

The current numbering plan would appear to be sufficient to cope with potential increase in demand for services for quite some time to come.

The Australian national trunk access code, 0, is not used for calls originated from locations outside Australia.

Notable are the part of New South Wales around Broken Hill (a large part of the state's area but less than 1% of its population), which uses (08) 80xx numbers,[2] and Wodonga, which is in Victoria but is within the New South Wales (02) area code.

Similarly New South Wales border towns including Deniliquin and Buronga are within the South East (Victorian) (03) area code, and Tweed Heads within the North East (Queensland) (07) area code.

Physical exchanges can be allocated one or more prefixes and modern technology allows sub-sets of these number ranges to be allocated to switching entities physically located at a distance from the exchange in which their controlling terminal is located.

Similarly, a person who dials 7010 5678 on a land-line or mobile phone in Melbourne (i.e., within the 03 area) will be connected to 03 7010 5678.

However, the full international number must always be dialled, since the Australian telephone network has the capability to recognise when the destination required is either international, in a different national area or within the local area and to switch and charge the call accordingly.

Prior to MNP, mobile operators generally reserved number ranges in blocks of 04 xy z.

In 2015 the 05 prefix (other than 0550) was also reserved for digital mobile phones as a part of the Telecommunications Numbering Plan 2015.

Parts of the 014 prefix had previously been used as a 9 digit, AMPS mobile phone access code.

The 01471 prefix is the ten-digit replacement for the previous, nine-digit ITERRA satellite phone code 0071 (followed by 5 numbers).

The following codes are not generally dialable from international points, but used in domestic dialling: Some notes: 000 is the primary emergency telephone number in Australia.

[13] In order to encourage use of 000, mobile telephones imported commercially into Australia are required to be programmed to treat 000 in the same fashion as 112 (i.e. dialling with key lock enabled, use of any carrier, preferential routing, etc.).

[14] On older or privately imported (e.g. roaming from another country) telephones, 000 may not receive such preferential treatment.

The recipient is usually charged at a set rate per second for each call, depending on plan and destination.

190x (not to be confused with 0198) is the prefix for premium rate services (e.g. recorded information, competition lines, psychics, phone sex, etc.).

These can range from a standard SMS cost (usually 25c), up to 55c for competition use, to several dollars for other uses, such as unique bid auctions.

Not all carriers have interconnect agreements with each other These codes are only true for Telstra-infrastructure based landline phones Many old numbers were officially removed from the Telecommunications Numbering Plan in the 2015 version, whether in the replacement version or a previous variation.

Other numbers for directory assistance, often with a call connection option, exist depending on the carrier.

See Collect call#Australia Up to this time, the maximum size of an Australian telephone number was six digits.

The use of a letter-number combination also served as a memory aid as it was easier to remember than a string of digits in the days when such things were not as common.

Since the initial digits of 1 and 0 (ten) were not used, this gave the telephone company concerned up to 8 regions with main exchanges and up to ten sub-exchanges in each metropolitan area – a total of up to 80 individual exchanges of 10,000 numbers in each with up to only 800,000 individual "numbers" in any metropolitan area concerned.

This former alphanumeric scheme was significantly different from the current system used for SMS messages.

Although Melbourne city numbers began with 6, it was only rarely, and probably by accident, that any other exchanges had matching letters.

Numbers using the old alphanumeric scheme were written as ab.xxxx, for example FU 1234 (the actual train of digits sent to the phone was "371234") or MW 5550 (685550).