Authorities in China are hunting a man who posed as a high-ranking government official and took part in all-expenses-paid junkets for years despite not holding the post, local media reported.

Middle-aged, clearly well-fed, and clad in the black suits beloved of Chinese bureaucrats, Zhao Xiyong posed as an official from the State Council, China's cabinet, touring factories and local governments, with free banquets thrown in.

But authorities in southern China's Yunnan province, where Zhao conducted most of his tours, apparently got wise to his deception, which apparently lasted over two years, and branded him an "imposter" on social media sites.

"Someone called Zhao Xiyong posed as the head of a State Council Research Office... made inspection tours and gave speeches," a local government office in Yunnan wrote on Sina Weibo, a Chinese equivalent of Twitter.

Pictures posted online showed Zhao, in his black garb, sitting behind a red table at an official ceremony, while another showed him expounding on a point of interest to delegates sitting around an oak conference table.

Zhao's years of tours included local universities, a power company and a vegetable farm, and he would give rousing speeches about economic development before enjoying lunch, the state-run China News Service reported.

"We received a notice from the city government to accompany him on a tour, that was the first time I heard of him," one local official told China News Service at the weekend, adding: "We had no doubts about him."

Local officials were not available for comment on the issue Tuesday.

Zhao was hired in 2010 as a consultant for an economic zone on the basis of his State Council credentials, reported the respected Chinese magazine Caixin.

Its unclear how Zhao was able to trick local officials into believing his story, but he could face up to 10 years in prison for his deception, the China News Service said, citing lawyers.

The General Office of Yunnan's provincial government posted a notice calling for "all relevant government departments" to "take timely measures to prevent and expose Zhao Xiyong's fraudulent behaviour".