Construction starts on the new bridge in Nelligen

After 57 years being the gateway over the Clyde River, the old bridge will be replaced by a new 349 metre, two lane Super-T girder bridge, due to be open for use by late 2023.

Minister Constance said the current bridge had done its job, but it was time to be replaced.

"It's really special for Nelligen to see this work start to happen given, unfortunately, the use-by date for this bridge has well and truly passed," Minister Constance said.

"At it's peak, 90 staff are going to be working onsite and it will be fantastic for the local community once completed."

Early work on the bridge project to stabilise and prepare the soft ground was completed in 2019, a springboard from which the major work can begin.

The $148 million project will also include upgrades to 1.4 kilometres of the Kings Highway at Nelligen, to improve the safety of the roads.

"We've seen, unfortunately, too many people hurt on our roads and the more we invest, the more we see road toll and crash rates come down, and that's the best thing for our community," Minister Constance said.

"This is going to be a very serious construction site, and everyone's going to have to be very, very careful in the next couple of years both on the roads and on the water at this site."

The existing bridge, built in 1964, will stay open for traffic while the replacement is built, and will be removed once the new bridge is complete.

In the next few weeks, a new temporary jetty and rock platform will be built to provide river access and Transport for NSW said the community would be able to access the water throughout the entire construction and demolition process.

The project, including removal of the old bridge, is expected to be finished by late 2024, weather permitting.