In March this year, the NSW government committed $4.5 million to lift and rebuild a 1.1 kilometre stretch of the highway at the Washpool, provided that they were re-elected during the state election.

With the Coalition returned to government, the funding promise is now a reality.

Minister for Regional Transport and Roads Paul Toole and Member for Northern Tablelands Adam Marshall confirmed the funding on Thursday during an inspection of the site with Moree mayor Katrina Humphries, Moree Plains Shire Council director of engineering Ian Dinham, RMS western director for transport Alistair Lunn and construction superintendent Steve Botfield.

The Washpool, located about 15 kilometres east of Moree, is one of the lowest points along the Gwydir Highway and one of the first sections of the road to be flooded. The road is often washed away during a flood event and has to be completely reconstructed each time, at great expense.

The state government funding will be used to install box culverts underneath the road to allow floodwaters to flow beneath the road surface, rather than destroying the road every time it floods.

"This is certainly going to help eliminate the road being damaged and closed, like it has in the past, from minor rainfall events," Mr Toole said.

"Adam Marshall has done a terrific job in lobbying for this funding and I look forward to seeing the design and construction commence in about 12 months time."

Cr Humphries has been lobbying for the Washpool to be upgraded ever since the 2011 and 2012 floods when it was the first section of the highway to go underwater and completely cut Moree off from the east.

"This is wonderful ... we're very grateful to receive this funding," she said.

"It has been on our wishlist for many years. It's the greatest connection for those in the east of the shire to the main centre of town. Now bring on the rain to test it out."

Mr Lunn said this is a great outcome for freight coming in from the east, particularly when the Inland Rail comes and more growers from the east will be looking to transport their product west to Moree, rather than going east.

"This road is key for connection," he said.

"It won't stop [the water] in a massive flood - in a massive flood you won't get through anyway - but it'll solve those smaller nuisance events."

Mr Lunn said planning will now begin, with construction to commence in about 12 months.

"There's a lot of planning that needs to be done; we don't want it to lead to more water problems at adjoining properties, so it'll be about nine to 12 months before we see any physical work," he said.

"We'll also use the money to look at what else we can do to flood-proof the Gwydir."