The two-level underground car park will provide the town centre with an extra 505 car spaces next to Woolworths.

Hibberson Street will be closed to all traffic between Gozzard Street and Gungahlin Place West from Tuesday, October 13 to Tuesday, December 8.

The upgrade is part of a multi-million dollar expansion of The Marketplace which will balloon the total area taken up to about 10,000 square metres, as revealed in a development application in November.

Centre owners the Vinta Group announced the expansion of the centre would include a new Kmart store and 25 specialty retail shops in the precinct after the application was approved in May.

The existing Woolworths car park has been closed since late July.

Roads ACT director Tony Gill said the closure would allow for the construction of a tunnel linking the new underground car park to the existing basement under Big W.

He said the works would also affect ACTION bus services at the town centre.

From October 12 buses at the corner of Kate Crace Street and Hibberson Street will be diverted around the construction site.

"This diversion is expected to add up to five minutes to bus running times."

Mr Gill said an alternative temporary car park was located off Anthony Rolfe Avenue opposite McDonalds. It included an undercover pedestrian link with direct access to the shopping centre.

"The ACT government is working with the developer to minimise the length of time Hibberson Street is closed to traffic and to provide maximum pedestrian access to the shops and facilities in the vicinity of the construction site," he said.

TAMS has warned Gungahlin bus commuters of minor delays and advised residents to plan ahead.

The directorate said shelters and seating would be provided at the temporary bus station.

For more information, visit www.action.act.gov.au.