"Wan Qingliang was dismissed from his post," Xinhua said, citing the ruling party's secretive Organisation Department, which does not have a website.

As Guangzhou's Communist Party secretary, Wan ranked above the mayor and was the most senior official of the top-tier city, the capital of the southern province of Guangdong, which neighbours Hong Kong.

The post has in the past been a stepping stone to higher office. Wan holds vice-ministerial rank and is one of 171 alternate members of the ruling party's 205-strong Central Committee.

Corruption suspects who are dismissed from their positions are usually later expelled from the party as a prelude to criminal prosecution, but the timescale can be variable.

Communist Party authorities have been waging a much-publicised anti-graft campaign since President Xi Jinping ascended to the leadership 18 months ago.

But critics say no systemic reforms have been introduced to increase transparency to help battle endemic corruption.

A commentary in the state-run Global Times on Monday said the Wan case "further intensified people's concerns about the degeneration of China's government officials".

But the article, under the headline "Keep faith in the nation's anti-graft campaign", said the growth of official corruption "doesn't mean the country's system is facing a major crisis".

"China's national pathway to prosperity and the fundamental political system remain firmly established, and the Chinese economic momentum still continues," it said.

Wan was once considered a rising political star, owing to his relatively young age for an official of his rank and for being part of the Guangdong Communist Youth League, the power base of former president Hu Jintao.

Wan built a career as a propaganda official in Meizhou, Guangdong – hometown of famed general and state leader Ye Jianying. Ye's family is believed to have retained political influence in the city since his death in 1986. Wan served in top posts in Jieyang from 2003 to 2008, including party chief.

It is widely believed that the probe into Wan may be linked to the recent interrogations of his former top aides. Former vice-mayor of Guangzhou Cao Jianliao was detained in December for corruption, along with a number of senior Jieyang officials.

Hours after Wan's detention, the party's official websites said Ma Xingrui, a Guangdong deputy party chief, would step in to lead the provincial capital, which is the third biggest city in China.

But authorities later deleted the posts, saying the appointment was unconfirmed.

Wan came under fire soon after he took the Guangzhou post in 2011, when he appeared to suggest that housing prices were too low. He told mainland media at the time that his monthly rent for a luxury flat was only 600 yuan (HK$750), despite the market price being five times that.

Additional reporting by Keith Zhai