A state Labor government would build a new $53 million high school at Medowie to cater for the area's booming population.
Land on Ferodale Road was acquired for the school in the early 1980s, however, successive governments have refused to invest in the project.
Port Stephens Council's 2016 Medowie Planning Strategy predicts more than 7,000 new residents will call Medowie home by the mid-2030s.
Medowie Public School is at 117 per cent capacity with 351 students and Wirreanda Public School is at 123 per cent capacity with 625 students.
Opposition Education Spokeswoman Prue Car confirmed a state Labor government would commence work on the project in the first term of government.
"The failure of the NSW Liberal Nationals Government to build a high school in Medowie after 12 long years is a clear example of what happens when a government doesn't listen to the community," she said.
"There is a clear need for this school. Education in NSW needs a fresh start, and for Medowie that means a public high school which only Labor will deliver."
The need for the school has featured in state election campaigns over the past four decades.
Port Stephens MP Kate Washington said the current state government had failed to deliver the project, which it had led the community to believe it would build in 2011
"In 2011 the Liberals tricked our community, by promising to kick off the project," she said.
"But after 12 long years of a Liberal National Government, Medowie's public high school is still missing.
"Meanwhile, the area has grown massively - everyone knows Medowie desperately needs a public high school, except the Liberals.
"The upcoming state election couldn't be clearer. If the families of Medowie, Williamtown, Karuah, Salt Ash and the Tilligerry Peninsula want to see a public high school built in Medowie, they should vote for Labor."
The Medowie High School commitment is part of Labor's plan to deliver new and upgraded schools in growing areas across the state.