The fight for the marginal seat of Port Stephens has ramped up again, with state Labor committing $600 million for a major roads project.

The opposition is promising to fully duplicate Nelson Bay Road in 8 years; depending on the party winning office at the next two elections.

The project would see duplication delivered in three stages: Medowie Road to Stockton, Williamtown to Bobs Farm and Anna Bay to Nelson Bay.

It comes after the Berejiklian Government in January announced $205 million to duplicate the stretch from Williamtown to Bobs Farm, promising work would start in 2019 and be completed within three years.

It followed a previous announcement in 2015, where then Premier Mike Baird said work would begin in his term of government for a $70 million duplication of Stockton Bridge to Anna Bay.

That project is yet to begin, and Port Stephens MP Kate Washington said voters cannot trust the Liberal-Nationals to deliver in the next term of government.

“The government has made all sorts of empty promises to our community,” she said, “they stood here in 2015 and said full duplication of Nelson Bay Road and we’ve not seen a thing.

“The only thing that we’re getting is a roundabout upgrade which won’t even be completed by the election,” Ms Washington said.

Works to upgrade the roundabout intersecting Nelson Bay and Medowie Roads are currently being carried out as part of the government’s road safety plan for the area.

NSW Shadow Roads, Maritime and Freight Minister Jodi McKay admitted the price tag of Labor’s three-part plan is currently based on estimates.

“It is an extrapolation based on what we believe it will cost…our commitment today is $600 million on the table and the full duplication now,” Ms McKay said, “if that means that there is more money required, we will put more money on the table…”

Work has been carried out on Nelson Bay Road since 2002, however motorists are still bottlenecked into single lanes, creating heavy traffic during peak holiday periods.