Visitors to Parliament House will be forced to pay for parking from November.
But the Department of Parliamentary Services is yet to confirm the cost of a stay at the building’s visitor car park.
Parking in the 325-space public car park, under the forecourt of the building, is currently free and limited to three hours.
Tender documents say the infrastructure will be installed in the Parliament House lot by late October and public pay parking will become operational from November 6.
But the start date is five weeks after pay parking will be introduced in the Parliamentary Triangle, raising the possibility the lot will be overrun with fare evaders.
Workers and visitors will be forced to pay for car parking on national land from October 1.
Tender documents said the Parliament House system would operate 24 hours a day, seven days per week.
A Department of Parliamentary Services spokeswoman said parking fees are still being finalised.
But tender documents reveal a draft range, which says the first two-hours are set to be free.
The price then steadily increases for each additional hour.
A two-three hour visit will cost $3, three-four hours has been priced at $5, four-five hours to cost $10, five-six hours to set a visitor back $15, and more than six hours will cost $20.
The daily maximum charge will be set at $20. From 9pm to 8am will be free.
Payment will be made at three pay stations or at validation machines.
The system will be policed by boom gates, with special height entry machines to distribute tickets to buses and minivans.
“The paid parking system is to be used for all visitors regardless of the purpose of their visit, including large buses, taxis, motorbikes and will operate 24 hours a day,” tender documents said.
The price range is more expensive than that imposed on public servants in the Parliamentary zone, where motorists will be hit with hourly fee of $2.50 and a daily rate of $12.
A Parliamentary Services spokeswoman said the department wanted to start pay parking at Parliament House “as close as possible” to the Parliamentary Zones start date.
“Our objective is to provide accessible car parking for visitors to Parliament House,” the spokeswoman said.
“Parking fees are being finalised, guided by recent advice from the National Capital Authority about their charges.
“Fees will be set in advance of installing the new paid parking system in the visitor car park at Parliament House.”
Parliamentary Services secretary Carol Mills has previously said the model would seek to safeguard tourist access to the building by discouraging long-term parking, while encouraging sightseers to visit the building.
Ms Mills also previously raised the prospect of the 2500 workers - including politicians, public servants, staffers and journalists - in Parliament House being slugged for parking sometime in 2015.