Prime Minister Malcolm Turnbull will urge premiers to strengthen their anti-terror laws at the first COAG National Security Summit on Thursday.
Most states and territories allow police to hold terrorism suspects for a week.
But Mr Turnbull will ask leaders to adopt New South Wales' model, which allows police to lock up suspects for 14 days.
"We need nationally consistent pre-charge detention laws so that those who seek to do us harm can be held to account no matter where they are," he said.
"It's vital that we have nationally consistent terrorism laws.
"I'm asking state and territory leaders to work with me to deliver safety and security."
Brandis, Keenan explore safeguards for laws
Attorney-General George Brandis previously raised concerns about constitutional difficulties with lengthy detention periods, when asked about one state proposal for suspects to be held for 28 days without charge.
"Detention without charge … for an unreasonably long period, could be seen to be a form of executive detention," he told AM in 2015.
"Punitive detention under Commonwealth law can only be ordered by a court."
But since then, it is understood Senator Brandis and Justice Minister Michael Keenan have explored safeguards that could be implemented.
While lawyers within the Attorney-General's Department have been involved in the process, it is understood formal legal advice has not been obtained.
"This Government continues to listen to our security agencies and counterparts in the states to ensure they have the powers they need to combat terrorism," Mr Keenan said.
New law to ban terrorism instructions
The Commonwealth will also propose a new law to ban the possession of terrorism instructions.
The offence would apply even if a person did not have the intent or capability to prepare or undertake the terrorist act.
"People who are using the internet to spread terrorist propaganda and instructions will be tracked down and caught," Mr Turnbull said.
"They must face the full force of the law"
First ministers will also be urged to harmonise their terrorism hoax laws and introduce a consistent period of imprisonment for the offences.