Chan, who represents the accountancy sector, said the letter accused him of being "the sinner of the nation" for which he would be turned "bloody and messy".

He said he did not take the letter - which he received on June 2 - too seriously though the matter was reported to the police. He has turned down a police offer of protection.

Chan said he was not sure whether the letter was in response to his speech in the Legislative Council in which he said he would never forget the June 4, 1989 crackdown on students, or because he had abstained from voting in the May 27 motion calling for all those involved in June 4 to be vindicated.

Chan, 54, the former president of the Hong Kong Institute of Certified Public Accountants, became a legislator last September.

Chan said he received the hand- written note containing the words "sinner of the nation."

"The letter said I will be killed and made `bloody and messy'," Chan said. "It is the first time I have received what appears to be a death threat."

Chan said it could be just a prank though he did pass it on to the police as a precautionary measure.

It is understood the letter was opened by one of his assistants.

In the Legco motion, which was discussed before the 20th anniversary of the June 4 crackdown, Chan broke the usual silence by the pro-establishment camp on the subject by saying he had not forgotten the June 4 incident. He also joined the one minute's silence advocated by the pan-democratic lawmakers in the Legco chamber together with medical representative Leung Ka-lau.

"I will not forget June 4 and it cannot be forgotten," Chan said.

He said the central government had not given a frank account of what had happened 20 years ago, adding that the Chinese authorities had used guns against students.

In 2007, former chief secretary Anson Chan Fang On-sang received a letter in which a razor blade was enclosed less than a week after she won a Legco by-election.

Earlier this month two men, Huang Nanhua, 50, and Ho Wai-kan, also 50, were jailed for 16 and three years respectively for their part in a plot to harm former Democratic Party lawmaker Martin Lee Chu-ming which involved underworld gun smuggling.