A letter from the Hong Kong Junior Police Officers' Association, dated Wednesday, coincides with more than four months of sometimes violent protests in the Chinese-ruled city, much of it aimed at the police.

"Hong Kong City" will be in Zhaoqing, one and a half hours by high-speed rail from Hong Kong, with the first phase expected to be completed by the end of next year, the letter said.

The developer, Agile Group, said it was talking to the Zhaoqing municipal government about the development which it said would provide retirement for all walks of life, not just the police.

In the past few weeks, demonstrators have hurled petrol bombs and other objects at police, who have responded with tear gas, rubber bullets, water cannon and several live rounds. One police officer was slashed in the neck with a knife.

Many protesters have accused the police of using excessive force but police say they have shown restraint.

A Hong Kong court granted an injunction earlier this week to ban anyone from blocking or damaging married police officers' quarters that have been targeted in the protests.

The Hong Kong City aims to provide a "high-quality life with low cost", the police association said in the letter, adding it would try to get a good price from Agile for its members.

The Hong Kong Chinese Civil Servants' Association was also involved in the collaboration, it said.

When asked about the plan, Acting Chief Superintendent of the Police Public Relations Branch, Kong Wing-cheung, said the developer wanted to sell the apartments in groups, to allow for discounts, and the two associations were talking to the developer about this.

He added that buyers would have to abide by the bribery prevention ordinance and other guidelines when they accept any benefits.

Agile said in an emailed statement it had entered into a letter of intent with the Zhaoqing government to build the community "featuring Hong Kong culture" in a diversified project.

An increasing number of Hong Kong people are moving outside the densely populated financial hub - one of the world's most expensive cities - to mainland China for cheaper and better retirement options, helped by faster transport links and an integration push by the Hong Kong and Chinese central governments under the Greater Bay Area initiative.

The former British colony returned to Chinese rule in 1997 under a "one country, two systems" formula, allowing wide-ranging autonomy for 50 years which the pro-democracy protesters believe is increasingly under threat.

(Reporting by Clare Jim; Additional reporting by Felix Tam; Editing by Paul Tait and Nick Macfie)