BEIJING (Reuters) - A Chinese investigative journalist who wrote reports critical of a state-controlled construction equipment maker has been sentenced to prison after being found guilty of defamation and bribery, according to state media on Friday.

A court in Changsha, capital of central Hunan province, has found Chen Yongzhou guilty of "fabricating and spreading falsehoods to damage the business reputation of others", state news agency Xinhua reported.

Last year, Chen published stories in New Express, a state-backed tabloid based in the southern city of Guangzhou, alleging that Zoomlion Heavy Industry Science and Technology Co Ltd had engaged in sales fraud, exaggerated its profits and used public relations to defame its competitors. The Changsha-based company has denied the allegations.

Chen was then detained by the police on suspicion of tarnishing the reputation of Zoomlion. He later appeared on state television confessing that he had accepted bribes for fabricating stories on the company.

A Zoomlion employee has publicly accused the company's hometown competitor Sany Group Co of planting those stories. Sany has denied any wrongdoing.

Chen's arrest, which coincides with a government clamp-down on journalists, lawyers and Internet users in China, has drawn public attention to the role and plight of whistleblowers as the country's leadership moves to eradicate graft.

Last year, New Express published two front-page pleas for police to release him, an unusually bold move that drew widespread attention and sympathy from the public.

The court in Changsha said Chen was guilty of accepting bribes of 30,000 yuan (S$6,240) but did not say who he accepted the bribes from. He was sentenced to one year and 10 months in prison and fined 20,000 yuan.

Zhuo Zhiqiang, who co-authored some Zoomlion stories with Chen, was sentenced to 10 months' jail and fined 10,000 yuan.

Chinese journalists say they are often intimidated, harassed or detained if they tread on politically sensitive stories.

In August, Mr Liu Hu, a Chinese journalist who also worked for New Express and had accused officials of corruption, was released after almost a year in detention.

China's Foreign Ministry said on Monday that a Chinese woman who helped with the German weekly Die Zeit's coverage of the protests in Hong Kong was working for the newspaper without permission and had been arrested on suspicion of "causing a disturbance".