The safety and capacity of the Princes Highway from Nowra south to the Victorian border was also mentioned as a priority initiative.

Infrastructure Australia's Infrastructure Priority List is the authoritative guide to the priority infrastructure investments Australia needs to secure a sustainable and prosperous future.

The state and federal governments have committed funding for a new $342 million bridge over the Shoalhaven River, with the winning construction firm announced earlier this month.

"The project has strategic merit as it supports local, regional and tourist traffic, and allows for more efficient movement of freight on this important highway," the Infrastructure Australia list stated.

The priority list report has outlined the importance of the bridge project, which will replace the 1881 built steel bridge for southbound traffic, especially as there are no other crossings of the river on the coastal plain.

The current concrete northbound bridge, built in 1981, will be rerouted for southbound traffic and a new four-lane concrete northbound bridge constructed immediately to the west (upstream) of the existing bridges.

More than 51,000 vehicles use the crossing every day, the report states, which is forecast to grow by 1.4 per cent per year between 2026 and 2036 and a further 1.2 per cent per year between 2036 and 2046.

"Heavy congestion is experienced on the Nowra Bridge and nearby Princes Highway intersections during the morning and afternoon peak periods, while crash rates along this route are also worse than the NSW average for the same class of road," the report says.

Read more:

"The major economic benefit of the project is travel-time savings for passenger and freight vehicles from improved capacity and traffic flows.

"The project would also improve safety on the road."

Infrastructure Australia has independently reviewed the business case and agrees the project's benefits would outweigh its costs, stating the existing southbound bridge cannot carry vehicles that are more than 4.6 metres tall or higher mass limit B-Double vehicles.

"Over-size vehicles have to use the northbound bridge with police escort, which closes access for northbound traffic," the report says.

"In the event that the Nowra bridge is unavailable, it is estimated significantly longer trips for users - at least an additional 100 kilometres for regional trips and up to 250 kilometres further for local trips.

"Congestion and stop-start traffic on the road is leading to far more crashes on this section of the highway (8.1 crashes per kilometre per year) compared with similar roads in NSW (1.6 crashes per kilometre per year).

"The casualty crash rate of 4.3 per kilometre per year is more than quadruple the state average of 0.9."

As well as the new bridge the project also includes widening the existing concrete bridge over Bomaderry Creek on the north side of the river, the realignment and upgrade of Princes Highway intersections with Bolong Road and Illaroo Road to the north and Bridge Road to the south, the closure of the existing Pleasant Way intersection and construction of a new access road and intersection connecting Lyrebird Drive.

The 1881 bridge will be closed to traffic and investigation of opportunities for adaptive reuse, such as pedestrian, cyclist and other community uses following a separate environmental assessment.

Upgrading the Princes Highway between Nowra and the Victorian Border was recognised as a priority initiative for safety and capacity.

The primary north-south connection between greater Sydney, Wollongong, the Illawarra-Shoalhaven region and the south coast of NSW, the highway carries a mix of freight and passenger traffic for local, long-distance and tourism trips.

Between Nowra and the Victorian Border, the highway experiences congestion, has a poor safety record and has freight productivity constraints due to the challenging topography, mass-limited bridges, and the two-lane, undivided road design, which offers limited overtaking opportunities.

An average of five fatalities and 40 serious injuries per year were recorded along the corridor over the last five years. Some sections register crash rates more than double the NSW median fatal and serious injury crash rate.

The Australian Government released the Princes Highway Corridor Strategy in November 2019, considering the entire length of the highway across NSW, Victoria and South Australia, which identified locations between Nowra and the Victorian Border as priorities for bridge upgrades and additional passing opportunities.

The initiative is for a program of works to make the corridor safer, and more efficient and accessible.

The Australian Government and NSW Government have committed funding towards the bypass of Moruya, the duplication between Jervis Bay Road and Sussex Inlet Road and a bypass of Milton and Ulladulla.

Infrastructure Australia also noted submissions had been received from Shoalhaven City Council in relation to the National Freight and Supply Chain Strategy for Beyond Nerriga and freight access to Bomaderry by rail, which were both submitted this year.