Labor Senator John Faulkner has accused the Department of Parliamentary Services (DPS) in Canberra of spying on him using CCTV cameras.

The comment came as Senator Faulkner and Liberal Senator Bill Heffernan detailed shortcomings in the security operations of Parliament House in Canberra during Senate hearings.

Those included Senator Heffernan bringing what he termed a "pipe bomb" into the Senate, a move aimed at highlighting his concerns about safety at Parliament House.

Senator Faulkner has a knack for extracting information from public servants in Senate hearings, and on Monday it turned out he was at the centre of a disciplinary investigation by the Department into one of its employees.

The head of the DPS, Carol Mills, said some of the CCTV footage may have captured the employee undertaking activities in the building "besides the one for which the CCTV was released".

Senator Faulkner grilled Ms Mills over the use of CCTV footage in that investigation. When she offered to discuss it in private, Senator Faulkner let fly.

Senator Faulkner: Alright. Does it involve me? Does it involve people providing information to me? Ms Mills: It may do Senator. Senator Faulkner: It may do? Does it involve a person or people or an individual or individuals providing information to me as I go about my work as a Senator in this Parliament? Ms Mills: That is what I'm looking in to Senator.

An angry Senator Faulkner calls it a serious breach of Parliamentary privilege that he has vowed to pursue.

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"I'm sure every Senator around this table understands what has just been said. A serious breach. That a Senator in this Parliament is being spied on in that way as they go about the proper conduct of their duties - no-one in this place is ever going to accept that," he said.

It is a matter that has been alluded to before, and stretches back to 2011 when, in government, the Labor Senator was leading an inquiry into Parliamentary administration.

On Monday, he asked another Parliament House official, Jenny Teece, for any information about the CCTV footage, but only as it related to him.

Jenny Teece: The relevance of the photos is that they demonstrate there was no need for access to the areas of Parliament House that [the employee] did if the sole purpose of her trip was ultimately to deposit material, which could only relate to personal business, under the door of Suite 42 on the outer corridor. Senator Faulkner: Who occupies Suite 42 on the outer corridor? Ms Teece: Senator I… Senator Faulkner: You don't know? Ms Teece: No, I… Senator Faulkner: Well, I do. I occupy it.

On the question of his Parliamentary privilege being breached, Ms Mills said she spoke to the clerk of the Senate on Monday morning when the matter emerged.

Senator Faulkner: What did the clerk say to you? Ms Mills: The clerk indicated to me that on face value it would be a breach of the guidelines, albeit potentially inadvertent. The outcome would technically be potentially a breach from what… Senator Faulkner: No question a breach of the guidelines…

Senator Faulkner says the clerk's advice to him included the statement: "The use of electronic surveillance of a Senator's office for unauthorised purposes to intimidate persons that provide information to Senators is also capable of being found to be a contempt."

Earlier in the hearings, Senator Heffernan said Parliament House is "no longer secure" and has labelled new security arrangements "a joke".

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

Previously, everybody coming into Parliament House had to be checked through security.