The United Nations said on Monday it was "alarmed" by detentions in Hong Kong linked to the 34th anniversary of the Tiananmen Square crackdown, while China said the financial hub was moving from "chaos" to prosperity.

Hong Kong police said they detained 23 people on Sunday for "breaching public peace", and also arrested a 53-year-old woman for "obstructing police officers" on the anniversary of the violent suppression of pro-democracy protests in Beijing in 1989.

The United Nations High Commissioner for Human Rights called on Twitter for the release of anyone detained for "exercising freedom of expression and peaceful assembly".

China's Foreign Ministry said in a statement late on Sunday that "today's Hong Kong is moving from chaos to stability and prosperity along the right track of "one country, two systems".

"External forces" including the United States should uphold international law and stop "futile political manipulation" over Hong Kong to contain China, a ministry spokesperson said.

Restrictions on speech and public protests in the administrative region of Hong Kong have stifled what were once mass candlelight vigils marking the anniversary of the Tiananmen crackdown, leaving cities like Taipei, London, New York and Berlin to keep the memory of June 4 alive.

Hundreds of police conducted stop-and-search operations and deployed armoured vehicles near Victoria Park, the previous site of yearly vigils.

Hong Kong activists say such police action is part of a broader campaign by China to crush dissent in the city that was promised continued freedoms for 50 years under a "one country, two systems" model when former colonial ruler Britain handed it back in 1997.

The United States Consulate posted a photograph on Facebook on Sunday of candles lined up in all of its windows. "In memory" it wrote.

The Canadian consulate said on its Facebook that it joined the people of Hong Kong and others around the world in "remembering the violent crackdown against unarmed and peaceful citizens" on June 4, 1989. It said Canada stood with all those "prevented from upholding their rights, including the right to assemble peacefully."

Hong Kong public broadcaster RTHK said that all 23 people detained on Sunday for breaching peace and public order offences were not arrested and were later released.