Plans to boost Hong Kong's cultural credentials by building a new branch of China's most famous museum in the city have sparked protests against what critics say is cultural brainwashing and kowtowing to Beijing.

The backlash comes at a time of heightened sensitivity in the semi-autonomous city where there is increasing concern that Chinese authorities are tightening their hold.

With its collection of ceramics, calligraphy, paintings, jades, timepieces and other items from multiple Chinese dynasties, Beijing's Palace Museum is the most visited in the world, with more than 14 million people coming through its doors each year.

Project organisers say a locally managed and curated Hong Kong branch, displaying artifacts on long-term loan from Beijing, would be a stellar attraction for the city.

But opponents argue the public should have been consulted before the green light was given to a project they feel has been developed to please Beijing.

Recent demonstrations against the plans have included protesters throwing paper tanks at officials, in a reference to China's Tiananmen Square crackdown.

The Palace Museum is housed within Beijing's Forbidden City, just north of the square where tanks rolled in to quash pro-democracy protests in 1989.

"It's not simply brainwashing -- it is cultural whitewashing by introducing more Chinese history and culture that is perceived to be positive," said Avery Ng, chairman of the League of Social Democrats.

Ng said the museum disregarded Hong Kong's identity "including its own history and the dark side of Chinese history".

Others say the public may have appreciated the museum if it had been discussed transparently.

"People appreciate museums and art if you do it in a proper way," said former legislator Lee Cheuk-yan, who organises the city's annual Tiananmen vigil.

He called the lack of public consultation over whether the museum should go ahead a "dictatorial approach".

- 'Diluting culture' -

The Hong Kong Palace Museum will be built in the West Kowloon Cultural District, a sprawling arts project already mired in delay and accusations of political interference. It replaces a performance venue originally slated for the area.

Set to open in 2022, it will be funded by a HK3.5 billion ($450 million) grant from the city's Jockey Club, which runs Hong Kong's horse racing meets, lottery and betting shops.

Hong Kong's deputy leader Carrie Lam is chairman of the cultural district authority's board and critics accuse her of pushing through the museum project to impress Beijing.

Lam is widely expected to run for city leader in March, with little hope of succeeding in her election bid without the nod from China.

But she has defended herself and the project.

"I know that today's society is full of mistrust, but for this issue, we really do not have any selfish motives and private interests," she told reporters Tuesday.

"We should not let this cultural issue be politicised."

A six-week public consultation into the design, operation and programming for the museum kicked off Wednesday, after criticism mounted, but it does not ask whether the project should go ahead. The board already approved plans for the museum in November.

City residents who spoke with AFP said they did not support the project.

"By building something like this they just want to merge us together," real estate agent Kong Lung, 27, said, adding he felt it was an example of the "mainlandisation" of Hong Kong that had taken place since the city was handed back to China by Britain in 1997.

"Every day since the handover you can see that mainland Chinese have been coming to Hong Kong and that's already diluted the Hong Kong culture," he said.

Others said they felt the museum plan was a political move.

"I don't see why they have to build the Palace Museum here, I don't see it to have any relationship with Hong Kong," said education publisher Danny Chung, 28.

"I think those responsible for it are trying to ingratiate themselves with those in Beijing," he added.