Foreign buyers will be included in a Victorian government plan to slash stamp duty on off-the-plan apartments, units and townhouses for 12 months to try to turbocharge home building in the state.

The expanded stamp duty concession will be uncapped and open to all buyers. The Allan government estimates it will cut the stamp duty paid by buyers on a new $620,000 apartment to $4000, representing a saving of $28,000. Treasurer Tim Pallas said the one-year stamp duty relief would cost the government $55 million.