Federal parliament's powerful intelligence and security committee is considering whether to let ASIO interrogate 14-year-olds.

The Law Council of Australia also raised concerns with allowing ASIO to plant tracking devices on people with only internal approvals.

The bill required careful scrutiny, president Pauline Wright told the committee in Canberra on Friday.

"We consider that additional statutory safeguards are required," she said.

Ms Wright said the council wanted stronger protections for children brought in for questioning.

She also suggested an independent judge should be given the final say on warrants to detain someone for questioning.

The ability to interrogate people after they had been charged with offences harmed their right to a fair trial, Ms Wright said.

She said at the very least, children should be barred from being questioned after being charged, while judges should sign off on questioning adults.

ASIO has emphasised the terror threat posed by teenagers as it pursues greater questioning powers.

It told the committee in a written submission that since May 2015, one terror attack and three disruptions involved people aged under 18.

"Vulnerable and impressionable young people will continue to be at risk of being ensnared in the streams of hate being spread across the internet," it said.

Human Rights Commissioner Edward Santow said there was no evidence the laws would have stopped the deadly 2015 shooting of NSW Police Force accountant Curtis Cheng by 15-year-old Farhad Khalil Mohammad Jabar.

"You have to find a balance here," Mr Santow told the committee.

"This legislation therefore requires stronger rather than weaker oversight."

Australia's intelligence agency watchdog said oversight was robust.

"We have found ASIO is very careful with complying with guidelines," Inspector-General of Intelligence and Security Margaret Stone said.

The legislation would lower the minimum age for questioning teens suspected of politically motivated violence from 16 to 14.

A lawyer would need to be present but could be booted from the room if authorities thought they were being too disruptive.

ASIO argued switching to an internal review model for planting tracking devices would bring it in line with state and federal counterterrorism partners.

Agents can already conduct compulsory interviews of terror suspects, but wants this extended to spies and foreign meddlers.

ASIO also said Australia's "probable" terror threat was unacceptably high.

It said while the main terrorism threat was from Sunni Islamist extremism, the threat from right-wing extremism was growing.

Australian Associated Press