Jat told the South China Morning Post the council wanted to be involved in demonstrations as early as the planning stage to facilitate discussions among the police, protest organisers and the media.

'If those who make complaints can come happily and leave happily with their anger vented, it is good for everyone,' he said.

The force was criticised for its recent use of pepper spray against protesters and for media arrangements during a protest outside the central government's liaison office, where only four television stations were allowed to use a media zone.

Jat hoped for a 'long-term and holistic mechanism' to facilitate communication, as he said complaints always came after a protest ended, which was too late.

He said he wanted to prevent arguments and clashes between police and protesters, which could arise from poor communication at the planning stage, such as when discussing the route of a march.

Jat also suggested the council play a role in monitoring officers' handling of a demonstration, including the use of violence against protesters, and said it should be involved in evaluating the police action afterwards.

Council members have discussed the proposed idea but not formally with the force.

The council needed to consider the personal safety of observers at violent clashes, Jat said.

He said it would be a priority for him to set up the mechanism during his term, which ends next month. If his contract was not renewed, he said, he believed his successor would continue the discussion.

Asked if protesters had turned violent in recent years or if police methods had not caught up with the times, Jat said: 'It takes two to tango. Whenever there are clashes, there is usually more than one reason.

'In a special political environment such as Hong Kong, it is really difficult to strike a reasonable balance among all the interests and demands.

'If anyone can do so, he should be the chief executive.'

Jat said he believed that if officers and demonstrators did not provoke each other, there would not be any clashes.

He observed that most of the participants in protests were law-abiding and rational but said it was inevitable that a small number of people would push and challenge the police to test their limits.

But he said the police had a responsibility to strike a balance between security concerns and freedom of speech and the press.

Jat pledged to continue to give advice to the police to revise their internal guidelines. One of the notable changes police had made after taking the council's advice, he said, was the use of larger and clearer warning signs before using violence against protesters.

A police spokesman said the force welcomed any suggestions that would enhance its communication with event organisers. It would discuss the suggested mechanism with the council, he said.

Law Yuk-kai, director of Hong Kong Human Rights Monitor, welcomed the proposed mechanism. He hoped it would prevent many disputes from arising during protests, saying that would be better than handling complaints afterwards.

'They can see a lot more on the frontlines than just merely sitting in the office handling complaints.' Law said his group would continue to deploy observers at big protests.

Eric Lai Yan-ho, convenor of Civil Human Rights Front, which organises the July 1 rally each year, also welcomed the proposal, saying it would help provide a check against the police abusing their power.

He hoped the mechanism could be set up as soon as the May 1 rally or June 4 candlelight vigil.