HONG KONG (AFP) - A Tiananmen Square protest leader was barred from entering Hong Kong on Sunday (June 2) after travelling to the city for a candlelight vigil marking the crackdown's 30th anniversary, organisers of the memorial said.

Other former student leaders from the 1989 protests have been blocked from entering the city before, according to local media reports, but a growing list of overseas activists and politicians have been refused passage into the semi-autonomous Chinese city in recent years.

Mr Feng Congde, a former student from the elite Peking University now living in San Francisco, landed in Hong Kong ahead of the annual memorial commemorating victims of the bloody 1989 crackdown.

The 53-year-old was stopped by immigration officers and eventually put back on a plane, said Mr Richard Tsoi, vice-chairman of the Hong Kong Alliance which organises the vigil.

Mr Feng said he had travel documents allowing him to enter Hong Kong legally, according to text messages sent to Mr Tsoi and shared with AFP.

Hong Kong "obeys the Chinese Communist Party", Mr Feng wrote in the messages.

"At a time when Hong Kong people are worried about human rights and freedoms violations, (this incident) only makes them more averse to the government," Mr Tsoi told AFP.

The Immigration Department declined to comment on the case but said it makes each decision "in accordance with the laws of Hong Kong and prevailing immigration policies".

Mr Feng had travelled from Tokyo, where he attended other Tiananmen memorials, and is due to return to the Japanese capital again on Sunday evening.

Hong Kong remains the only territory on Chinese soil where crowds are allowed to gather in public to commemorate the bloody Tiananmen crackdown.

The city enjoys freedom of speech and assembly rights unseen on the Chinese mainland under a 50-year handover agreement between former colonial power Britain and China.

Activists fear those liberties are being eroded as Beijing flexes its muscles and stamps down on dissent.