The operator of the national broadband network claims the lab trials of the technology, DOCSIS 3.1, on the HFC network — previously Telstra's pay TV cable — achieved downstream speeds of 1Gbps “on par with the top speed available for retailers on the NBN fibre-to-the-premises (FttP) network".

As well as Sydney and Melbourne, NBN Co is touting gigabit speeds will also be delivered to Brisbane, Adelaide, Perth and the Gold Coast.

NBN Co says the trials, in Melbourne delivered upstream speeds of 100 Mbps – more than double the current highest 40 Mbps upload retail speed available on HFC retail services over the NBN network.

According to NBN Co, the NBN it will be one of the first operators outside the US to commercially launch DOCSIS 3.1 technology as an upgrade path for the HFC network and able to deliver gigabit+  downstream wholesale speeds.

NBN Co says it is planning further lab testing of DOCSIS 3.1 in August, then in-field trials in December, ahead of a potential commercial launch of DOCSIS 3.1 services in 2018.

According to NBN Co, chief executive Bill Morrow will enable the company to bring gigabit broadband to premises “far more quickly, cost effectively and with less disruption” to end users than alternate technologies in busy urban areas.

"DOCSIS 3.1 is going to be able to provide fantastic gigabit potential  for end users – just as our fibre-to-the-premises (FttP) network does today.

“This is another example of the continued efforts of the NBN team to innovate and plan for Australia's growing demands for data.”