Hong Kong's famed Chinese white dolphins face environmental catastrophe unless moves are made to protect their habitat from a rash of construction projects.

The warning comes from the World Wide Fund for Nature, which is calling for Tai O and the Soko Islands of Lantau to be declared marine parks.

WWF says environmental impact studies for 10 impending infrastructure and leisure projects covering northern Lantau fail to address the affects they will have on dolphins.

Their habitat stretches from Lantau's western, southern and northern shores to the Tuen Mun coastline.

WWF wants the Hong Kong- Zhuhai-Macau Bridge impact report, due for completion by the middle of next month, to be reworked to include a more in-depth review of the cumulative effects of several big construction projects.

"Even though there have been major reclamations before, none of them has cut right through the middle of the dolphin grounds. You just can't predict the impact on the dolphins of such a massive development in their midst," said WWF senior conservation officer Alan Leung Sze-lun.

Noise pollution is one of the leading causes of mortality among dolphins and Leung said this, together with the dredging and piling that will displace small fish the creatures eat, will be a double blow.

The city's western waters are home to more than 1,000 white dolphins.

WWF's call for new marine parks follows a 2002 endorsement by the Country and Marine Parks Board. The Agriculture, Fisheries and Conservation Department said reviews into the impact on the dolphins were ongoing.