They were informed an hour before 80 participants for a run in remembrance of the June 4, 1989, incident arrived at 1pm.

Patrick Kwok Pak-chung, senior superintendent of the Police Public Relations Branch, said only four television stations could enter the zone owing to lack of space.

'We have to strike a balance between public order and facilitating the media's needs,' he said.

Non-television reporters had to either retreat to another media zone further away from the office's entrance or squeeze their way through the protesters who gathered on the narrow pavement.

The police changed their initial decision only after some non-television reporters entered the restricted media zone and refused to listen to the officers' advice to leave.

Mak Yin-ting, chairwoman of the Journalists Association, criticised the police for restricting press freedom.

'The arrangement divides the media and discriminates against non-TV reporters,' she said. 'Even if space was limited, reporters could work out among themselves as to where to do their reporting. Do the police think of themselves as the chief news editor of Hong Kong?'

Since last year, police have imposed more restrictions on covering protests outside the liaison office, limiting reporters to a press zone far from the rallies.

At a protest earlier this month, officers forbade reporters to approach the protesters.

The association is compiling a report taking a position against the designation of media zones and will submit it to the Independent Police Complaints Council.