It also coincided with Beijing's admission for the first time that visa controls for foreigners entering the mainland had been tightened, a move described by Foreign Ministry spokesman Qin Gang as ensuring 'a safe environment' ahead of the Beijing Olympics.

In a paper for the Legislative Council security panel, the government said Hong Kong, as a co-host city of the Olympics, had an obligation to ensure that related activities would proceed in a 'safe, peaceful and smooth manner'.

'The torch relay is part and parcel of the Olympic Games. The government does not welcome it if any person seeks to damage the solemnity of the Olympics or disrupt the smooth proceeding of the relevant Olympic activities in Hong Kong,' it said.

Discussing the paper at a special meeting of the panel, lawmakers demanded an explanation for the turning away of several foreign activists, despite statements from some that they would not seek to disrupt the torch relay.

Panel deputy chairman Democrat James To Kun-sun challenged the government to 'come clean' on whether there was a policy change to ban foreigners participating in political activities in Hong Kong, even though such activities were legal.

Secretary for Security Ambrose Lee Siu-kwong said last month that anyone pushing for Tibetan independence and those seeking to split the nation would not be welcomed.

In the past fortnight, at least eight nationals of western states - including Danish sculptor Jens Galschiot and his two sons, two Britons, two from Canada and one from Sweden - had been denied entry.

Democrat legislator Cheung Man-kwong said the government's failure to give adequate reasons for the refusals of entry, while allowing Hollywood human rights activist Mia Farrow to visit despite her outspoken views on China, was a double standard and had damaged Hong Kong's international image.

'The government's silence is a shield to hide the fact that such measures have damaged the 'one country, two systems' [system],' he said.

But Chan Kam-lam, of the Democratic Alliance for the Betterment and Progress of Hong Kong, said some foreigners should be banned in light of incidents such as the World Trade Organisation protests in 2005.

More than 11,000 foreigners were refused entry between January and April, according to the government. A total of 39,508 were turned away last year.

Deputy Secretary for Security Grace Lui Kit-yuk admitted the government had a 'watch-list' of people whose entry 'may not be conducive to the public good'. But she stressed that not everyone on it would automatically be banned. 'The government will not turn away people because of their political views.'

Mr Qin said China had made 'some arrangements' on visas according to the practice of past Olympics and usual international practice.

'This policy does not mean that all multiple-entry visas have been suspended,' he said, without elaborating. 'This policy will be maintained for a period of time in order to ensure China will have a safe environment.'

Central government officials have not previously confirmed such a tightening of visa requirements, despite repeated requests from business chambers and frequent travellers to clarify the issue.