Parliament guards working 16-hour days

Parliament House security guards have been spending up to 16 hours a day on their feet since last year's security upgrade.

Department of Parliamentary Services officials have confirmed some security personnel have worked double shifts since the changes came into force.

Liberal Senator Cory Bernardi quizzed department secretary Carol Mills during a Senate estimates hearing about the additional overtime.

"So the people entrusted with Parliament House security in some instances are required to be on their feet for 16 hours?" he asked.

"Yes, Senator," Ms Mills responded.

Senator Bernardi said he was concerned about the physical and mental effects working that long can have on guards, despite their professionalism.

"I think there's a link between ... the dumbing down of security, the relaxation of security in this place and the circumstances in which some of our officers now find themselves," he added.

Ms Mills said double shifts were being reduced through the hiring of more staff.

An independent review of rostering was also taking place to "minimise demands on staff that are unreasonable", she said.