HONG KONG (AFP) - Hong Kong democracy activists have found an unlikely new way to get their message across - using the words of the founder of Communist China, Mao Zedong.

As concern grows that semi-autonomous Hong Kong's freedoms are under threat from Beijing, two large red political banners carrying quotes from Mao that purport to be in favour of democracy have appeared on roadside railings, close to China's liaison office in the city.

Emblazoned in yellow on the banners, the phrases "Abolish one-party dictatorship" and "Exercise democratic politics", are taken from Mao's Order And Conversation On The Southern Anhui Incident in 1941, which saw nationalist troops attack communist forces.

Mao used the term "democracy" before he came to power in 1949 as a way to galvanise public support, but on taking the helm installed one-party rule.

Lawmakers in Hong Kong are allocated banner space by lottery for their term and the liaison office spot went to pro-democracy legislator Au Ngok Hin.

The banners were made by Mr Au's campaign coordinator Sam Yip.

"Au and I wanted to remind the officers in the liaison office that this is the way for China to become prosperous and strong, and Mao said so," Mr Yip told AFP.

The banners were also a response to pro-Beijing figures on both sides of the border who have said anyone calling for an end to one-party dictatorship would run the risk of election disqualification, Mr Yip said.

Activists in the city have a history of coming up with inventive ways to promote their views.

Huge pro-democracy banners regularly appear on the city's famous Lion Rock, although they are quickly taken down.

Pro-democracy artists also managed to install a controversial light show on Hong Kong's tallest building two years ago which counted down to 2047 and was swiftly removed.

The year 2047 will be a watershed for Hong Kong as it will see the end of the 50-year agreement signed when Britain returned Hong Kong to China in 1997 and which enshrines the city's freedoms and way of life.

So far the Mao banners, put up on May 10, are still intact and are technically allowed to remain until the end of Mr Au's term in 2020.

Hong Kong's legislature is partially directly elected and its mini-constitution gives rights unknown on the mainland, including freedom of speech.

But the prosecution of pro-democracy activists, the ousting of rebel lawmakers from the legislature and the banning of some opposition candidates from running for office have shrunk the space for political expression.