The Government confirmed an attempted breakout at High Island 13 days ago had prompted a further review of security arrangements.

'This is a high-priority exercise, as the intention is that any additional physical measures should be implemented as quickly as possible,' a government spokesman said.

Any structural changes will be made before September when the north Vietnamese population left in Whitehead is transferred to High Island as part of the camp closure system.

All southerners will be housed in Whitehead after September when Tai A Chau camp, with 5,600 southerners, is closed.

In July last year, 90 people made their escape from High Island in the early hours of the morning during a heavy rainstorm.

An official inquiry found it was organised by a small group, but many inmates escaped when they realised the Correctional Services Department had not noticed the break in the fence.

Compared with the May 10 Whitehead escape and riots, damage was minimal in the High Island breakout.

The Government confirmed it had received 77 claims for compensation arising from the May 10 Whitehead incident which were now being considered 'as a matter of priority'.

Insurance will not cover the losses, which included damage to dozens of private cars belonging to Correctional Services officers, because of a clause which made the policy null and void in times of riot.

'Government property, which was damaged or destroyed during the riots will be replaced where appropriate and the costs involved will be met from public funds,' the spokesman said.

'The total cost of repairs and security improvements in Whitehead has yet to be finalised, but is likely to be in the order of about $50 million.' High-security isolation units made of brick are already being constructed at Whitehead and High Island to house troublemakers.

About 16,000 boat people remain in Hong Kong.