Opposition leader Jodi McKay was in Singleton on Thursday to make the announcement alongside Upper Hunter candidate Jeff Drayton and shadow roads minister John Graham.

The NSW Government's current proposed bypass is set to include a southbound exit ramp and a northbound entry ramp at Putty Road.

"What the people of Singleton and the Upper Hunter are getting is pretty much half an interchange and that half an interchange means that Singleton CBD, the businesses here will suffer greatly," Ms McKay said.

"We believe that whichever direction you are coming from you should be able to get into and out of Singleton and that's the interchange that we believe should be constructed."

Ms McKay said the $25 million figure came from the government's own estimate and "may sound a lot" but was a drop in the ocean compared to projects such as the $3 billion Sydney light rail.

The full interchange is one of two key concerns Singleton Council has raised about the project, the other being that the road will not initially be built as dual carriageway, with the project's land acquisitions allowing for it in the future.

Ms McKay stopped short of committing to dual carriageway, but said a Labor Government would immediately start construction of the project, which was initially earmarked for completion in 2017, but is now estimated to be ready by late 2026.

"By the time they deliver it, it will be some 10 years late," Ms McKay said.

Mr Drayton said the project should be completed as soon as possible with a full interchange.

"You need to be able to access town when there's a bypass from both ways," he said. "You need to be able to get in and get out of Singleton regardless of whether you're coming from the south or the north.

"And it is a concern as we understand from the business community in Singleton.

"Anyone that can make a decision to continue to put this project off for as many years as they have obviously isn't anyone who's ever driven in this traffic of a morning or ever driven in this traffic of an afternoon."

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