A key Senate crossbencher has accused Australia's intelligence agencies of creating "moral panic" and is worried new national security laws will allow ASIO to torture people.

Liberal Democratic Party Senator David Leyonhjelm said the laws, which are due to come before Parliament soon, allow for barbaric interrogation techniques.

"I mean torture and I am not kidding," Senator Leyonhjelm said.

"So there is a provision in this act which says ASIO agents, and those authorised by ASIO, can do anything except murder, serious assault or sexual offence.

"If you have interrogation which involves, say, temperature extremes, sensory bombardment, sensory deprivation, sleep deprivation, drugs, water boarding, physical torture techniques that [are] short of causing death or serious injury ... they could all be used with impunity."

Senator Leyonhjelm has long been opposed to giving intelligence agencies greater powers.

He told The World Today he is not "against" today's terror raids in Sydney and Brisbane but does think the nation's spies have created a "moral panic" to push their agenda.

"I do blame the agencies for it. They have convinced the Government," he said.

"The agencies already have a lot of power, they can question people in secret ... there are already very strict laws against violent crime.

"Why do they need more?"

Senator Leyonhjelm is one of the crossbenchers the Abbott Government needs to pass contentious pieces of legislation.

If the national security laws pass in their current form, he claims he will no longer give the Abbott Government "the benefit of the doubt" on other bills.

"Since the first of July when I became a senator I have tended to give the Government the benefit of the doubt," he said.

"More often than not I think the Government has the mandate and unless [bills] are totally offensive to my libertarian principles ... I've tended to vote with them.

"I have to say a Government that thinks it's OK to authorise torture worries me a great deal and I would reconsider that attitude."