Protesters gathered at a sports stadium Sunday as Hong Kong braced for more anti-government rallies, a day after clashes returned to the city's streets following several days of relative calm.

Hong Kong has been gripped by three months of street demonstrations that started against a proposed extradition bill to China, but have spun out into a wider pro-democracy movement.

Beijing has used a mix of intimidation, propaganda and economic muscle to constrict the protests in a strategy dubbed "white terror" by the movement.

The MTR -- the city's metro -- is the latest Hong Kong business to be rebuked by the public, after appearing to bend to Chinese state-media attacks accusing the transport system of being an "exclusive" service to ferry protesters to rallies.

On Sunday the MTR said it would close stations near the main demonstration area in Tsuen Wan, the second day of station closures in a row.

A second rally of a few hundred, some of them relatives of police, was also held on Sunday afternoon.

One relative, who said she was the wife of an officer, said they had received enough criticism. "I believe within these two months, police have got enough opprobrium."

"I really want you to know even if the whole world spits on you, we as family members will not," she said, giving her surname only as Si.

"Remember, your job is to serve Hong Kong residents, not be the enemies of Hong Kong."

Hong Kong's officers are often the focus of protesters' anger because of their perceived heavy-handling of the rallies.

Ten people were left in hospital after Saturday's clashes -- two in a serious condition -- staff said, without detailing if they were police or protesters.

Saturday's clashes saw police baton-charge protesters and fire tear gas, while demonstrators threw rocks and bottles later into the night in a working-class neighbourhood.

The city had appeared to have pulled back from a sharp nosedive into violence, with the last serious confrontation taking place more than a week ago, shortly after protests paralysed the financial hub's airport.

Demonstrations started against a bill that would have allowed extradition to China, but have bled into wider calls for democracy and police accountability in the semi-autonomous city.

Protesters say Hong Kong's unique freedoms are in jeopardy as Beijing tightens its political chokehold on the city.