The managing director of the Dorman Shipyard, Tony Chan To-chan, said the shipyard owners had lodged a claim with the Board of Appeals against the ban, which, he said, made their work almost impossible.

Mr Chan said they had asked the consultants to look into alternative methods of noise reduction to avoid having to move the shipyards.

He estimates the move will cost in excess of $500 million and cripple Hong Kong's port and shipping industries for at least two years while the shipyards are closed and unable to carry out their usual maintenance duties.

He said one option might be to double-glaze the windows of the adjoining housing estates.

'There is a school right beside the shipyards on the other side and we asked them if they had any problems with the noise,' he said. 'They said they could hardly hear our noise because all their windows are double-glazed.' The EPD said it had received 49 complaints about the noise over the past five years.

The District Officer of Kwai Tsing, Andrew Wells, who negotiates with the shipyards and the nearby residents, said he welcomed the shipyard owners decision to call in an independent consultant.

'The Government assessment generally is that nothing short of a full-scale relocation will do the trick,' he said. 'However, it is an encouraging sign that the shipyard companies themselves are prepared to spend some money in looking at environmental improvement measures.' He said it would be helpful if the study also included environmental measures that could be taken after the yards moved to the new site to further reduce noise during working hours.

He said the Government would also welcome any suggestion for noise abatement in the short term.

However, he said he hoped the shipyard owners would not simply use the report as an excuse for further delays in moving.