The nation's top spy agencies are warning that the number of cyber security threats facing Australia is increasing by the day.

The Australian Cyber Security Centre (ACSC) partners with agencies including ASIO and the Federal Police.

In its first unclassified report it has revealed there were more than 11,000 cyber security incidents affecting Australian businesses last year.

More than 150 of the incidents involved critical infrastructure and so-called systems of national significance.

The ACSC said it saw "daily" cyber espionage activity targeting Australian Government networks but "Australia has not yet been subjected to any activities that could be considered a cyber attack".

It said: "Destructive cyber attacks could be considered equivalent to an armed attack, and therefore, an act of war."

The centre urged Australian businesses to guard against the risk of cyber threats and said banks and energy companies were among the most targeted firms in 2014.

"To combat the threats detailed in this report and reduce the risk of compromise, organisations must move now to implement cyber security measures to make Australia a harder target, increase the confidence of Australians when they are online, and maximise the benefits of the internet for Australian organisations," the centre said.

Communications Minister Malcolm Turnbull said he welcomed such reports.

"It's important that all of us are aware of the risks of cyber crime and a lot of the basic internet hygiene that you can practice will protect you against much of it," Mr Turnbull said.

"Make sure all of your software is up to date, all of your applications are up to date, don't open attachments from anyone without being sure they're from someone you know and trust."