A senior National Party MP says while he is a great fan of  more dams in New South Wales , he will never support the construction of the Welcome Reef storage on the upper reaches of the Shoalhaven River.

The issue of Welcome Reef was raised, and found some support, at the National Party state conference, which was held in Bowral over the weekend.

Kiama Liberal Gareth Ward has threatened war with his coalition colleagues,  if proposals for the dam at O'Allen Ford near Nerriga, ever get past first base.

Roads Minister and Government leader in the Upper House Duncan Gay says Welcome Reef would never be an effective storage.

Mr Gay says the dam would be too shallow, and subject to very high rates of evaporation.