The judge, sitting in the Court of First Instance, said Hong Kong was not bound by the principle of nonrefoulement, or non-return.

He said the rule had not attained the status of a peremptory norm - one recognised by the international community as a whole and which all jurisdictions must follow - and it had not been incorporated into the laws of Hong Kong.

Therefore, the judge said, the government was not obliged to follow the rule and conduct a screening of all refugee claimants.

'The rule against refoulement is a rule of customary international law. I think it goes too far to hold - at this time - that the rule has acquired the status of a peremptory norm,' Mr Justice Hartmann said. 'Put another way, the ideal does not accord with present reality and, if the ideal is to prevail, it may bring the norm itself into disrepute.'

The applicants had claimed that even though Hong Kong has not signed the 1951 UN Convention on the Status of Refugees, it was still bound by the broader principles, including non-refoulement.

They said the government's policy of outsourcing refugee claims to the United Nations High Commissioner for Refugees instead of having a system of its own violated customary international law.

But the judge noted that the policy allowed the Director of Immigration to exercise his discretion to determine any refugee claim on humanitarian or compassionate grounds.

'If, in any particular case, the director has reason to believe that he should not act upon a determination made by the [UNHCR], whether favourable or unfavourable to a claimant, he does not have to act upon it,' the judge said.

'He can ask that the determination be reconsidered, or he can ignore it.'

Human rights lawyer Mark Daly, representing the applicants, said it was very likely that they would appeal.

'The consequence following this judgment is that the status quo will remain, which we find very unsatisfactory,' said Mr Daly, who had argued that a fair, transparent and appealable assessment of refugee claims must be part of a jurisdiction's efforts to abide by the principle of non-refoulement.

The Hong Kong office of the UNHCR declined to comment on the independence of the Director of Immigration in determining refugee status.

A spokesman for the Security Bureau said the government had a firm policy of not granting asylum.

'Hong Kong is small and densely populated. Our unique situation, set against the backdrop of our relative economic prosperity in the region and our liberal visa regime, makes us vulnerable to possible abuses if the UN convention ... were to be extended to Hong Kong,' he said.

China has been a signatory to the refugee convention since 1982 and has extended the convention to Macau. It has been signed by 150 other countries.