A shuttle bus ferrying Home Affairs public servants around Canberra each day will expand its route as it replaces a service costing nearly half a million dollars.
Bureaucrats at the agency will travel between its offices in Barton, Civic, Braddon and Belconnen on buses seating at least 11 people on two services each hour through the national capital.
The new 24km bus route, operating weekdays in business hours, will also take public servants to the new Australian Border Force headquarters at 3 Molonglo Drive, Canberra Airport after bureaucrats move there.
Home Affairs has expanded its bus route for staff since finding a business to transport public servants between its offices in Civic and Belconnen in 2015.
It did not reveal the yearly cost of its shuttle bus route on Friday but a three-year contract to drive its public servants between Belconnen and Civic cost $420,000, a figure revised up from $370,000 in May this year, according to a contract notice.
The department has confirmed it would expand the shuttle bus route when the new Border Force office opened at Brindabella Park.
"The shuttle bus service is by far the most cost effective option for the movement of staff between offices to perform their work duties," a spokeswoman said.
Ninety staff used the shuttle service daily and the average cost per trip was $5.30 per person, she said.
Home Affairs public servants are scattered throughout 11 offices in Canberra but will merge into five once the move into its new Molonglo Drive building is finished.
It wants to centralise its bureaucrats in fewer buildings, a change justified by expected savings, as another major federal employer the Defence Department looks at cutting costs by spreading its workforce through outer Canberra.
The then-Immigration Department hired local transport outfit CBD Chauffeured Transport in 2015 to drive its public servants between the old Customs headquarters in Civic and Immigration's long-term office accommodation nine kilometres north in Belconnen.
Upon merging with Customs to form Border Force, Immigration wanted a new 80,000 square metre building no further than 10 kilometres from Parliament House and hoped to bring its 5500 Canberra-based public servants together in a single location.
A fierce bi-partisan political backlash combined with pressure from commercial interests in Belconnen scuppered any move of the 4000 Immigration public servants based there.
Commonwealth property guidelines also changed as a result of the saga so that "local impacts" must now be considered in any significant move.
The state-of-the-art building at Canberra Airport was a compromise, and Immigration - which became Home Affairs in December - said it would move 1500 Civic-based public servants there once it was finished.
The Molonglo Drive fit-out was due to begin in August this year and finish by February 2021. The upgraded building is expected to house 6000 staff.