Australian government departments have likely been hacked and do not even know it, a cyber security expert warns.
Michael Sentonas of CrowdStrike, the company that helped discover the damaging Democratic Party email hack during the US presidential election campaign, has little doubt some systems have been compromised and the breach has gone undetected.
"I think most of the federal government departments will be having someone knocking on their front door day in, day out," he told AAP.
While lots of money and resources have been directed toward tools and technology to defend attacks, less has been spent on detecting basic breaches.
Mr Sentonas believes most people do not have the ability to understand if they have already been compromised and who was behind the hack.
"It's such a basic thing to say but it's just not being done," he said.
The longer an attacker had been inside a network, the harder it was to get rid of them and know how much damage they had done, Mr Sentonas said.
It also gave them a chance to establish a stronghold and make it harder for the government to detect.
"If you don't know someone's on a network, obviously you're blind to whatever it is that they're doing - and that's not a good thing," Mr Sentonas said.
For government, it is essential to know who the attacker is to understand their motivation, what tools they have used and what they could do on the network.
Mr Sentonas stressed the need for governments to do a breach assessment, even if it only exposed opportunities for hackers to get into the system.
"Understanding the current state of your network has to be the starting point," he said.
Liberal MP Andrew Hastie, a member of parliament's intelligence and security committee, said the Turnbull government had a cyber-security strategy and invested $230 million toward Australia's capabilities.
"There's a lot state and non-state actors seeking to undermine the West, particularly the 'Five Eyes' (intelligence alliance) to gain economic or political leverage through cyber attacks," he told Sky News from Washington on Friday, following meetings with the FBI, CIA, Pentagon and other national security officials.