The attacks have targeted all levels of the government, political organisations, essential service providers and operators of other critical infrastructure, Morrison said in a media briefing in Canberra today.
"We know it is a sophisticated state-based cyber actor because of the scale and nature of the targeting," he said.
Morrison said there were not a lot of state actors that could launch this sort of attack, but Australia will not identify which country was responsible.
Australia's Defence Minister Linda Reynolds said advice showed no large-scale personal data breaches from the attack.
The revelation comes after Reuters reported Canberra had determined in March last year that China was responsible for a hacking attack on Australia's parliament. Australia never publicly identified that source of the attack and China denied it was responsible.
A US security ally, Australia strained ties with its largest trading partner, China, by pushing for an international inquiry into the source and spread of COVID-19 that first emerged in the central Chinese city of Wuhan late last year.
