The declaration means the state government will now assess the application for 5,100 new homes and open space.

Minister for Planning and Minister for Homes Anthony Roberts said Huntlee is the Hunter's first new town on more than 50 years.

The first stage is creating 2,700 homes, the local shopping centre, pub and parks.

If approved, this second stage could not only see the delivery of thousands of new homes, but also the completion of the Huntlee town centre, more community facilities and open spaces for the community to enjoy.

Mr Roberts said the development will inject $850 million into the economy over two decades and provide regular construction work with up to 400 homes built each year for the next 15 years.

Around 5,800 hectares of land would also be preserved to provide important habitat for the regions plants and animals, Mr Roberts said.

Now the project has been declared State Significant, developers will be required to lodge their development application with the Department of Planning and Environment.

It will be subject a thorough assessment and extensive community consultation.

If approved, development applications for further stages of the project would be submitted to the relevant council.