NSW opposition leader Luke Foley says he supports the government's push for significantly tougher anti-terror laws but wants to see more detail about why periods of detention should be increased.
NSW Premier Mike Baird has written to the prime minister saying the state government wants terrorism suspects to be able to be kept in custody for up to four days without charge, with a court able to extend the period to 28 days.
He's also seeking to lower the age threshold for control orders from 16 to 14 years, which Mr Foley said on Tuesday he supported.
He said he wanted further discussions with police and the government about extending the time for which people can be held without charge.
"We don't want to give the violent extremists the ability to say to Muslim kids that you can be locked up for a month just because you're Muslim," he said.
"We need to build community cohesion, that has to involve tough laws to combat terrorism but we would certainly like to hear a detailed explanation from the government on why the current provision needs to be extended."
Under current federal laws, a terrorism suspect can be held in custody for up to four hours before a court application needs to be made to extend the detention to up to eight days.
Mr Baird wants Australia to adopt laws similar to those in place in the UK, following the fatal terror attack at Parramatta on October 2.
"The act of terrorism at Parramatta was a clear demonstration that we need to strengthen powers to prevent terrorist acts and improve law enforcement's ability to respond to the changing terrorism environment," he said in statement.
Meanwhile, an 18-year-old terror suspect remains in police custody and can be detained until Thursday after federal police were granted a fresh order from a Sydney court on Monday.
The teenager was arrested last Wednesday in connection with investigations into 15-year-old Parramatta shooter Farhad Khalil Mohammad Jabar.
"We need tough laws to combat terrorism but we also need to ensure that we don't throw out the very freedoms that the terrorists seek to destroy," Mr Foley said.