Former guards from Australia's detention centre in Nauru have accused Wilson Security of providing misleading evidence to Parliament.
The ABC's 7.30 Program reports more guards have come forward saying a spying operation on the Australian Greens senator Sarah Hanson-Young was more extensive than Wilson Security had admitted.
The guards say the surveillance involved up to eight staff and continued throughout the senator's full three-day stay on Nauru in December 2013.
Their accounts differ from concessions made by Wilson Security to the parliamentary inquiry in June that a so-called operation was "confined to an unauthorised observation from the car park" for 12 hours.
The former guards say their orders were to follow and photograph the senator and note who she met and when.
One former guard told the ABC Wilson Security had made it clear anyone who spoke to the senator would be dealt with.