Development company Connectland Pty Ltd has offered to upgrade Bong Bong Rd and plans to put in extra crossings, to alleviate the daily traffic congestion which frequently backs up on either side of the railway crossing near Dapto station.

In exchange, the developer hopes to build a $700 million "employment and teaching centre".

On a sprawling 50ha site, the planned centre would combine classroom learning, on-the-job training and accommodation.

Under the plan Bong Bong Rd would be elevated above one-in-100-year flood levels and a new bridge would be built across Mullet Creek.

The railway crossing on Bong Bong Rd would be removed and a new bridge built over the railway line.

Connectland is hoping to negotiate an agreement with government authorities which would include these measures.

The Department of Planning is considering the proposal.

If successful, the plan may go some way to solving two of the outstanding issues in West Dapto: traffic congestion and flood access.

Residents have been agitating for the Fowlers Rd bridge since the 1984 floods, when waters rose 2m in places - 50cm more than 100-year levels - cutting off residents in the twin communities of Horsley and Dapto.

The need for flood access has become more pronounced in recent years as the NSW Government pushes ahead with plans to settle 16,000 families in West Dapto.

A recent report by the NSW Growth Centres Commission rejected the need for the bridge, finding instead that "timely, affordable and adequate flood-free access" could be achieved using a package of roadworks.

Connectland is confident it can overcome the flooding issues.

Cardno Forbes Rigby director David Laing, who is working on behalf of Connectland, said the flood risks could be handled on site.

"Our early indications are positive," he said.