Chinese police have detained a well-known poet and seven other people ahead of a poetry reading planned in Beijing to support pro-democracy protesters in Hong Kong, relatives of the detained said.

Police apprehended poet Wang Zang in front of his Beijing home on the night of October 1 and then searched his apartment and confiscated a computer, a router and other materials, his wife Wang Li told the AP news agency on Wednesday.

On September 30, Wang had posted on Twitter a picture of himself raising his middle finger and holding an umbrella, a symbol of solidarity adopted by the protesters demanding open nominations for Hong Kong's chief executive elections.

A message over the picture read: "Wearing black clothes, bald and holding an umbrella, I support Hong Kong."

Lawyer Sui Muqing said his client was detained for "provoking trouble," which he said carries a sentence of up to three years in prison.

"It's likely related to the picture," Sui said. "It has to do with the Hong Kong protests."

Wang had been scheduled to speak at an October 2 poetry reading in Beijing's Songzhuang art district billed to support Hong Kong protesters.

According to relatives, police apprehended seven others on their way to the event, including Chinese journalist Miao Zhang and artists Zhu Yanguang and Fei Xiaosheng.

Yang Wong, the brother of publicist Melanie Wang, said his sister was detained while heading to the event, which never started, and was being held at the Beijing No. 1 Detention Center for seeking to disturb public order.

Wang Li said she had not heard from her husband since his detention, and Sui said he was not sure when he would be available to meet with his client.

'Always watched'

At least 37 people in mainland China have been detained for supporting the protesters, including posting pictures and messages online showing solidarity and planning to travel to Hong Kong to join protesters, according to human rights group Amnesty International.

Another 60 have been called in by police for questioning.

Wang Li said she and her husband had been repeatedly harassed for criticising Chinese officials and supporting workers' rights.

"In Beijing, we're always watched,'' Wang Li said. "We've moved eight times. Police have knocked on our doors. They've left us with no way to live."

Police officials said Wednesday they could not comment on the reported detentions.

Mainland Chinese media have tightly controlled information about the protests in Hong Kong, which peaked with tens of thousands of demonstrators, but have subsided after presenting Chinese leaders with their biggest political challenge in decades.

Only after several days of unrest did Chinese television and newspapers started to show pictures and video from Hong Kong's streets, but with protesters already dispersed, while only quoting critics of the demonstrators.