The ACT Greens have announced a plan to reserve grasslands and yellow box/red gum woodland at Throsby in Gungahlin.

Environment spokesman Shane Rattenbury said yesterday the amount of land protected from development in the new suburb would depend on an assessment of its conservation value. He said the Greens recognised the importance of releasing new land for development in Canberra, but the people of Gungahlin also deserved to enjoy bushland close to home.

''It's not about saying we don't want to release land, or we want to lock up all the land, it's about striking that balance that we've done so brilliantly in the rest of Canberra,'' he said.

It came as part of the Greens' biodiversity protection strategy, which also included reserving grasslands and yellow box/red gum woodland in Kinlyside.

Mr Rattenbury also called for the ACT to develop a biodiversity offsets policy. Larissa Nicholson