Occupy Central activists will face quarter of Hong Kong's 28,000-strong police force

At least a quarter of the 28,000-strong police force will turn out to handle the possible chaos should the Occupy Central movement for democracy carry out its threat to block streets in the main business hub later this month, sources close to the matter say.

The deployment would be the largest police operation since the city mobilised 9,000 officers during six days of World Trade Organisation meetings in 2005.

It would also be a near doubling of the police numbers deployed during the July 1 democracy march this year and the overnight sit-in on Chater Road on July 2.

The police plans come amid warnings by Occupy organisers in recent days of bringing Central to a standstill should the National People's Congress Standing Committee arrive at a framework for the 2017 chief-executive election later this month that does not offer a genuine choice of candidates for voters.

While police vacated their posts to converge on Central, the force would assign about 1,000 auxiliary officers and hundreds of retired officers - recently hired as station assistants - to maintain normal policing services, sources said.

The Police College in Wong Chuk Hang will be turned into a temporary detention centre, with room for 3,000 prisoners.

One police source said the force was discussing whether the Correctional Services Department could provide a facility to house detainees.