More than 1,000 people protested for a second day in central China on Thursday over pollution from a chemical plant that they say has sickened locals and poisoned surrounding farmlands, residents said.

Residents of the town of Zhentou in Hunan province demonstrated outside local government headquarters and a police station, demanding greater compensation for pollution from the Xianhe Chemical Plant, protesters said.

The protesters also said they came out to reject recent government health checks conducted on locals that officials said showed the situation was not serious, said a resident who gave only his surname, Chen.

"More than 1,000 people came out over the past two days. We do not believe the government health check reports. Also, the compensation they are offering is too low and the soil is already polluted," he told AFP by phone.

Rapid economic growth in recent decades and routine flouting of rules have taken their toll on China's environment, say activists.

China sees tens of thousands of public protests each year, many tied to anger over polluting industries.

State-run Xinhua news agency quoted Hunan officials saying the plant had been plagued by environmental problems since opening in 2004.

These included releasing large amounts of highly toxic heavy metals such as cadmium into the local environment. The plant was ordered to close in March of this year, it said.

Thursday's protesters also demanded the release of six people detained during protests on Wednesday, Chen said.

A female official reached by phone at Zhentou government headquarters defended the steps taken by authorities.

"We have already done a lot of work on the pollution issue and announced compensation, but some people do not accept it," said the woman, who gave only her surname, Luo.

"Instead, they spread rumours and inflate the problem. We do not know what they are up to."

A local villager who also gave his surname as Luo told AFP his family of five had received 5,000 yuan (735 dollars) in compensation.

"That is too low. We demand that the government move us to a safer location," he said.