Muslim legal representatives have warned using control orders on terrorism suspects as young as 14 could be damaging and will not be as effective as other measures to stop de-radicalisation.

Federal Parliament's Joint Committee on Intelligence and Security is conducting an inquiry into the Government's latest round of proposed counter-terrorism laws.

The bill would lower the age of control orders for terrorism suspects so that children as young as 14 could be subject to curfews, forced to wear a tracking device or prevented from seeing certain people.

Muslim Legal Network (MLN) president Zaahir Edries told the hearing in Canberra that he had concerns about the bill.

"Primarily because subjecting children to control orders will in practical terms further marginalise and alienate people who are already feeling disconnected from society," he said.

"We know from examples in the United Kingdom that the use of control orders can make subjects hostile towards investigative agencies and this is particularly damaging in the case of children."

He said community intervention is more effective than policing at preventing children from being radicalised, and the application of a control order was "not a small thing".

"It can't be over-stated how detrimental to the development of a young person the application of any types of control orders," Mr Edries said.

But Federal Police told the hearing they have evidence of control orders leading to positive changes in people's behaviour.

AFP Assistant Commissioner Neil Gaughan said that was the experience with two people who remain the subject of control orders.

"The persons are no longer associating with people that we would consider undesirable and secondly, those people would appear to actually be going down a different path ie. employment, listening to their family members, listening to what we call respectable members of the community," Commissioner Gaughan said.

He said recent examples, such as the 15-year-old gunman who killed police accountant Curtis Cheng and the arrest last week of a 15-year-old on terrorism offences, highlight the need for the changes.

"Control orders are almost a second last resort, the last resort being arrest so we will try and steer people away from those as much as possible but unfortunately it's a tool we need in our toolkit."

The Muslim Legal Network also raised concerns about the scope of the advocating genocide offence, saying it had the potential to impact on free speech.

"It pushes those discussions [about terrorist organisations] underground which is dangerous, they should be open to criticism and open to be challenged," MLN vice president Rabea Khan said.

The Law Council of Australia gave evidence calling for greater safeguards around the control order regime as a whole, and as applied to children as young as 14.

Best interests of child should be 'primary' factor in decision

It has suggested the bill be amended to require courts to consider the best interests of the child as the "primary" factor in deciding if a control order should be granted.

This includes their age, culture and benefit of the person to have a meaningful relationship with their family.

Committee member Liberal MP Philip Ruddock suggested the potential to be involved in a terrorist act should also be in a child's best interests.

"Isn't it equally a primary consideration that you protect the child where you can from being engaged in terrorist acts which fundamentally take away their future life expectancy," Mr Ruddock asked the Law Council.

"If we saw an event in Australia that could have been prevented, of what we saw in Paris and we hadn't acted to put in place measures to try and prevent it when we'd been counselled that these were necessary, I regard that is a pretty significant issue."

Human Rights Commission President Gillian Triggs reiterated her opposition to the legislation, saying it should not pass in its current form.

"The purpose of the counter-terrorism laws is ultimately to protect the human rights of all Australians and those under Australian jurisdiction," she said.

"We should not risk undermining democracy while purposing to defend it in these ways."

The intelligence and security committee will report in February.