'Up to the present moment, we have not rejected Mr Ma's application ... If there was an application, we have not rejected it,' he told an RTHK radio phone-in programme.

Mr Lee said he had been informed that Mr Ma had postponed the visit, but this claim was denied by city officials in Taipei.

However, Mr Lee would not confirm that Mr Ma had applied for a visa. 'We do not comment on individual cases. We will deal with [any] application later,' he said.

He also declined to say whether Chief Executive Tung Chee-hwa had sent officials to Taipei to urge the mayor to cancel the trip.

Mr Lee's remarks prompted the Taipei city government to increase pressure on the Hong Kong government to grant Mr Ma a visa.

City government spokesman Yu Tze-hsiang said Mr Ma had submitted his visa application together with the members of his entourage. 'The accompanying staff members have already obtained their visas, but Mr Ma has not got his yet.

'If it has not been rejected, [the Hong Kong government] should issue the visa as soon as possible.'

The visa row made headlines last week after Mr Ma said he could not attend a University of Hong Kong seminar today and a conference to be held by the US-based Committee of 100 on Thursday. The committee focuses on Sino-US relations and has invited former US defence secretary William Perry and mainland officials to attend.

In an interview with Commercial Radio, Cheng Anguo, a former Taiwanese envoy in Hong Kong and now director of the Taipei mayor's office, said the applications were submitted to the Hong Kong Immigration Department via a Taiwanese travel agency on December 24. Mr Cheng said that while some Taipei officials who planned to accompany Mr Ma had already received their visas, neither he nor Mr Ma had yet received any notification of approval or refusal. Some observers earlier said Mr Ma's recent criticism of the mainland's planned anti-secession law could be the reason his visa had not been approved.

Mr Ma revealed he had been visited by two groups of people from Hong Kong who suggested he call off the trip, but he refused.

Observers believe another reason is that Mr Ma's presence at the Sino-US relations forum would give the wrong message, amounting to 'one China, one Taiwan'.

Pro-democracy lawmakers said Mr Lee's latest remarks did not help clear the air. Democrat James To Kun-sun said: 'The secretary was only making a very technical point. The government might never process the case and therefore it's technically correct to say the government never rejected it.

'For such a sensitive case, the government must have conveyed its message to the parties concerned at an early stage. It doesn't have to formally put a chop on the form to reject an application.'