Triple Zero (000) is the primary national emergency number in Australia. The Emergency Call Service is operated by Telstra a condition of its telecommunications licence, and is intended only for use in life-threatening or time-critical emergencies. Other emergency numbers in Australia are 112 for GSM mobile and satellite phones, which is answered by a Triple Zero (000) operator and 106 for TDD textphones. Triple Zero (000) was also the emergency number in Denmark and Finland until the introduction of the 112 number in 1993.

For calls to the State Emergency Service the Australia wide number 132 500 can be used (except for in the Northern Territory). This number should only be used for non life threatening situations.

Prior to 1969, Australia did not have a national number for emergency services; the police, fire and ambulance services possessed many phone numbers, one for each local unit. In 1961, the office of the Postmaster General (PMG) introduced the Triple Zero (000) number in major population centres and near the end of the 1980s extended its coverage to nationwide. The number Triple Zero (000) was chosen for several reasons: technically, it suited the dialling system for the most remote automatic exchanges, particularly outback Queensland. These communities used the digit 0 to select an automatic trunk line to a centre. In the most remote communities, two 0s had to be used to reach a main centre; thus dialling 0+0, plus another 0 would call (at least) an operator. Zero is closest to the finger stall on Australian rotary dial phones, so it was easy to dial in darkness.