The $140 million River Street bridge would start from from Thompson Street, near the Newell Highway, along a new road and follow the river bank. It would then cross the river to connect to the highway near River Street.

Nationals candidate for Dubbo Dugald Saunders said the bridge would be about 545 metres long and designed to cope with a one in 25 year flood.

Mr Saunders said the River Street option was the best option because "it was the number one option".

"There were six options that were looked at, there were two options taken off the table very quickly after community consultation because they would not work for the community, this one will work for the community going forward," he said.

NSW Roads Minister Melinda Pavey said there was a "hell of a lot of work" that went into picking the River Street option, however she said more consultation would be undertaken if the project progressed.

"We've done our homework, we've done our planning and we will do more work with the community. That's our job and we need to do that, but this bridge will get built under us," she said.

People needed to understand why RMS had designed the bridge, Ms Pavey said.

"You have a few people who are critics, they get a really loud voice and people get concerned but when people understand the forecasts, the planning and the work that's gone on that this is a really good solution," Ms Pavey said.