The state government on Friday created a new prisoner designation – a "national security interest inmate" (NSI) – to crack down on prisoners deemed at risk of inciting or organising terrorism via their contact with the outside world.

The new powers allow NSW Corrective Services Commissioner Peter Severin to impose severe restrictions on the ability of prisoners who have not been convicted of terrorism offences to communicate with visitors, friends and family.

The powers could see minimum security inmates hit with some of the same restrictions as high-risk inmates already convicted of a terrorism offence.

The commissioner will be able to impose the restrictions if he considers there is a risk that the prisoner could engage in or incite others to engage in "activities that constitute a serious threat to the peace, order or good government of the state or any other place".

A national security interest (NSI) designation means visitors would need to be approved with a criminal record check, while an inmate's mail would be opened, read and copied and mail and phone calls would have to be in English or another approved language.

The commissioner can change an inmate's designation to NSI without seeking recommendations of the Review Council.

"We are introducing these strong measures to help prevent inmates from co-ordinating terrorism activities or inciting extremism from inside prison. We will not take a backward step when it comes to ensuring community safety," said Corrective Services Minister David Elliott​.

"While there is no known specific terrorist threat from inside our prisons, the new NSI designation will give Corrective Services NSW the ability to better monitor all inmates who pose a risk to national security, throughout their time in custody."

The changes come almost a month after radicalised teenager Farhad Khalil Mohammad Jabar shot dead police accountant Curtis Cheng outside NSW Police headquarters in Sydney.

This month, Premier Mike Baird wrote to Prime Minister Malcolm Turnbull urging him to extend the time a suspect may be held without charge from up to eight days to 28 days and lower the age threshold for control orders from 16 to 14.

Control orders can be used to restrict movements, contact and activities of terrorism suspects and allow their monitoring.

Federal Attorney-General George Brandis has said the Commonwealth will introduce legislation to lower the control order age threshold but has indicated potential constitutional problems with extending the pre-charge detention period.

On Friday, the President of the Lebanese Muslim Association, Samier Dandan, criticised the further crackdown on inmates.

He said the government's current policy "seems to be more focused on policing and control than trying to address issues at a grass-roots level".

"We don't want to keep seeing the same process that focuses on policing," he said. "The academics are telling us the only way to address this is on a social basis."

NSW Council for Civil Liberties president Stephen Blanks said he believed the new designation was "counter-productive".

"This kind of regulation is going to make reintegration more difficult because it will build up opposition and resentment from the prisoners concerned and their families, whose communications with them will be inhibited."