Senior officers in the Department of Parliamentary Services (DPS) monitored CCTV coverage of Parliament's internal corridors to access nine minutes of footage while investigating a departmental officer suspected of leaking information to Senator Faulkner.

In a fiery public hearing of a Senate committee on Monday, Senator Faulkner confronted the head of DPS, Carol Mills.

In a half-hour long grilling, Ms Mills confirmed that a potential breach of the rules around the use of CCTV had occurred during a disciplinary investigation into a former staff member working in Parliament. But she declined to elaborate on why the person was under investigation.

''All right, does it involve me? Does it involve people providing information to me?'' Senator Faulkner asked.

''It may do, Senator,'' Ms Mills replied.

''This is the most serious breach,'' Senator Faulkner said.

''A senator in this Parliament has been spied on in that way as they go about the proper conduct of their duties.

''This is a serious issue of parliamentary privilege. I will stop my questioning on that matter at this point and I flag with the chair and the president … I will be taking this matter forward as a matter of privilege immediately.''

It is not the first time allegations have been aired that potential whistleblowers making contact with Senator Faulkner have been tracked by DPS staff have surfaced.

In 2011, Fairfax Media reported that departmental insiders alleged that security cameras were used by the Parliamentary Services department to try to identify whistle-blowers leaking information to Senator Faulkner, who was then driving an inquiry into parliamentary administration. Parliamentary officials denied that any surveillance had taken place.

Ms Mills said the department's internal management procedures could ''inadvertently come into conflict'' with the privileges of MPs.