ACT transport minister Meegan Fitzharris said the territory would provide up to $100 million to improve the highway, after the Turnbull government also promised $100 million for the road in its May budget.

Ms Fitzharris said the highway would be duplicated in some parts,  and could include improved connections to the airport.

"We really welcomed the Commonwealth investment in the Monaro Highway in their most recent budget, we weren't expecting it so we do have some further work to do with the Commonwealth but there are some particular areas of focus that we know about already on thee Monaro Highway

"Those will include shoulder widening intersection safety upgrades as well as looking really important link around the airport there to see if we can improve the important east-west connections at the airport there now that we have such terrific north, south improvements with the Majura Parkway."

Ms Fitzharris also announced the duplication of William Slim Drive, from Ginninderra Drive to the Barton Highway, with approximately 3.2 kilometres of new carriageway, 6.4 kilometres of new on-road cycle lanes and a new bridge over Ginninderra Creek.

However the government was yet to put a dollar figure on the upgrades as they were in talks with the Commonwealth.

"The construction funding will be in the budget but is provisioned for two reasons, for commercial reasons and the other is to progress discussions with the Commonwealth about their proposed land release of the CSIRO site here," Ms Fitzharris said.

"The ACT government strongly believes the Commonwealth needs to make an investment in surrounding infrastructure to coincide with their fairly quickly planned release of land here at the Ginninderra CSIRO site. The ACT government's view is the Commonwealth must contribute to infrastructure upgrades in the surrounding region if they are going to go ahead with this significant land release in Canberra."

Ms Fitzharris said there were already 20,000 vehicle movements a day on William Slim Drive and the CSIRO release would put more pressure on the road network.

However she said she was "optimistic" they could negotiate funding with the Commonwealth.

Ms Fitzharris said the government had also set aside $4 million to improve intersections on Belconnen's Kuringa Drive and Owen Dixon Drive.

The government had earlier announced $4 million to install traffic lights at two intersections on Tillyard Drive.

Another $1.25 million has been allocated to designing an extension of John Gorton Drive and a bridge across the Molonglo River.