Liberal Senator Bill Heffernan has revealed he has taken a mocked-up pipe bomb into Parliament House to show up problems with new security arrangements.

Under the new system, some passholders and their belongings are not scanned when entering the building.

Previously, everybody had to be scanned to come into Federal Parliament.

Senator Heffernan says the building is “no longer secure”, and told a Senate estimates hearing he brought a fake pipe bomb and dynamite through Parliament’s security this morning to demonstrate his concerns.

“Clearly you can do what you bloody well like,” he told the Senate estimates committee hearing in Canberra on Monday.

“I don’t think it any longer is (safe) and to demonstrate that, this morning I brought in what could be, I brought this through security – a pipe bomb,” he said.

Liberal Senator Bill Heffernan says Parliament is no longer secure due to security budget cuts.. brought a “bomb” in today to demonstrate.

— Karen Barlow (@KJBar) May 26, 2014

The NSW senator said when he was a kid on the farm he used explosives to blow tree stumps out of the ground.

“We could blow a tree the size of this building out of the ground,” he said, detailing the ingredients for his home-made bombs.

“At the present time, there is nothing to stop anyone from bringing those ingredients in here over a period of time through security.”

Australian Federal Police Commissioner Tony Negus, who is appearing at the committee, said “that is a risk, yes”.

Mr Negus later said Senator Heffernan had showed him his supposed bombs before the hearing and he was satisfied they were inert.

He said that was why there was no reaction from his officers in the hearing room “who in different circumstances might have responded quite differently.”

“I wouldn’t encourage others to try and make that point because it might not be so responded to,” he said.

The committee heard one of the reasons behind the change was to save money.