The retractable bollards caused $28,935 of damage to Comcars in three "human error" incidents in November last year. Two other incidents have also been recorded, including an Australian Federal Police vehicle and a maintenance vehicle.

The problems emerged when the automated system was turned off, with the bollards hitting the cars from underneath as they drove over. The system was turned to manual deployment due to interference caused by works to build the security fence around Parliament House.

The damage includes a smashed transmission system and a pierced undercarriage, which is shown in the images released under Freedom of Information. Parliamentary Services said no MPs were in the cars damaged, and no one was injured in the incidents.

The documents released show that two Comcars were damaged at the front, while the rear of one vehicle was damaged.

Comcars provide chauffeured transport for the Prime Minister, the Governor-General, members of parliament, judges and guests of government.

The bollards were installed in 2005, separately to the $126 million plan to increase security at Parliament House that is under way.

The bill for the damage was picked up by the government's insurance fund, with $500 excess paid for each vehicle to Comcover.

The documents also showed an email that called the issues with the bollards a "financial cost to the Commonwealth, loss of asset and reputational concern".

The Department of Finance told a Senate estimates hearing in February that an audit into the deployment of the bollards had been called after the incidents.