'To use tear gas was excessive. It is an image that will look terrible for Hong Kong around the world.' There is also concern that yesterday's clashes will influence the US Congress in deciding whether to allow the entry of 20,000 Vietnamese for resettlement before 1997.

The proposal has already been criticised by the British and Hong Kong governments as well as refugee groups, who fear repatriation effort will be undermined and that more refugees will pour out of Vietnam in the hope of finding a better life in the United States.

Lawyer Pam Baker said the authorities had badly mishandled the move, claiming the refugees should have had a week's notice to allow their anger to subside.

Legislator Miriam Lau Kin-yee approved of the transfer to speed up the closure of Whitehead but questioned the heavy use of tear gas.

Legislator James To Kun-sun called for a review of government procedures for the transfer of inmates. 'What will happen when the authorities try to take them to the plane?' he asked.

Non-governmental organisations (NGOs) called in to monitor the operation refused to comment. They were compiling reports which are expected to be issued today and later this week.

But Refugee Concern feared the full story would never be known because monitoring was inadequate.

A government report after the controversial Whitehead operation in April last year said independent observers should monitor all moves.

But Ms Baker said most monitors did not speak to the Vietnamese and couldn't tell what was going on.

The group said different NGOs and Justices of the Peace were sent on each operation. 'Where is the means of comparison?' he asked.

'This will be the sixth report produced by the monitors since the policy was implemented. The first took a week to produce and was completely superficial. It used euphemisms like 'controversial behaviour'.' But a government spokesman said: 'Continuity is not necessary. Different JPs are called in for each operation to ensure objectivity.'