The New South Wales Opposition has indicated it is likely to vote in favour of new counter-terrorism laws the State Government has introduced to Parliament, but said it needs to look at the fine print first.

Key points: Suspect can be held for a maximum of 14 days

Suspect can be held for a maximum of 14 days A judge can extend detention period by seven days at a time

A judge can extend detention period by seven days at a time The powers will be used as the basis for a national model

Under the legislation, NSW Police will be able to detain and question terrorism suspects as young as 14 without charge for up to two weeks.

Labor Leader Luke Foley said, at first glance, the legislation appeared more reasonable than the 28 day detention period the State Government originally proposed.

Changes were put forward in the wake of the fatal shooting of police accountant Curtis Cheng at the NSW police headquarters at Parramatta last year.

"What's come back today, on the face of it, seems to be a more balanced and reasonable proposition, that does protect the community while providing the necessary balances that we need in our democracy," Mr Foley said.

"So we're inclined to look favourably on what's been announced but we do have to do our job and scrutinise the fine print."

When introducing the laws to Parliament, Premier Mike Baird said police had discovered problems with the existing counter-terrorism laws when they made a string of arrests as part of an investigation into alleged terrorism plots in Sydney.

"Since using the preventative detention provisions and applications during Operation Appleby, the NSW police identified some critical operational gaps" Mr Baird said.

"We must address these operational gaps. This bill does so, giving increased powers to NSW police to keep our community safe."

Laws give police ability to 'properly investigate' plots: Premier

Mr Baird said in a statement the new police powers would give officers the time to investigate terrorist plots and acts before suspects were released back into the community.

"We have to do everything possible to protect our community from terrorist threats and these new powers do exactly that, by giving our police the ability to properly investigate terrorist plots," he said.

Deputy Premier and Minister for Justice and Police Troy Grant said police were supportive of the new laws, which would allow officers to keep up with the threat of terrorism.

"This legislation, if I can make this very, very clear, will only be utilised when there is imminent threat to our community from terrorism," Mr Grant said.

"All the appropriate safeguards are in place to make sure these laws are not misused.

Mike Baird says the stricter anti-terrorism laws would give the police the ability to properly investigate terrorist plots. ( AAP: Lukas Coch )

Mr Grant said if the increased powers had been available earlier, they could have helped to prevent the murder of police accountant Curtis Cheng.

He said the new laws would allow police to protect the community when there were similar "red flags".

Former Independent National Security Legislation Monitor Bret Walker said the new laws were appropriate and the age threshold of 14 was not too low.

"I'm satisfied from my researchers and from looking at international comparators that the safeguards in these laws are at least as good, arguably better, than most of those that exist elsewhere," he said.

"Unless we persuade ourselves that 14-year-olds do not commit such offences, then we really do, however reluctantly with whatever sorrow, we really do need to have to confront the possibility of laws to permit this."

Laws will be resented: NSW Council for Civil Liberties

The NSW Council for Civil Liberties president, Stephen Banks, said the proposed laws will isolate communities alongside vulnerable, young Australians who instead need support and they will be "resented".

"It will obviously be seen as unfair and alienating by the very people that we need to bring into the system in order to prevent terrorism," he said.

"They can either decide that Australia is against them and they want to fight against our community, or they can be brought into the community and be given every encouragement and incentive to join with the rest of the community.

Mr Blanks said the proposed shift to allow holding periods to be extended by seven days at a time, instead of being subject to a judge's approval every 48 hours, is "contrary to the interests of the community".

"The police, when they deprive individuals of their liberty, do so under the supervision of an independent arm of government - that is the judiciary," he said.

"That is such a fundamental aspect of our free society... and here we are throwing it away."