Construction of the line ceased 20 years ago when Liberal premier Nick Greiner refused to allocate funds to the project.

Thirlme re resident John Macrae has led the Wollondilly campaign to have the line finished.

Mr Macrae said the line must be completed for the sake of safety as well as the financial prosperity of the state and the country.

``They're planning 4000 new homes at Wilton, the port is expanding and all the imported cars are going to come from down there up to Sydney by road, plus all the coal from the Appin and Douglas Park mines,'' he said.

The Federal Government is conducting a feasibility study into the line to determine the cost and viability of finishing it.