A Chinese whistleblower has called for a thorough investigation into a Chongqing sex video scandal after it emerged more officials have been seen in secretly filmed footage.

The scandal was initially made public on November 20 after a video featuring one official, later confirmed to be Lei Zhengfu, Communist Party chief of Beibei district of the southwestern Chongqing Municipality, went viral online.

Lei was removed from his post three days after.

Zhu Ruifeng, an independent investigative journalist, brought the scandal to light and he runs a whistleblowing website "People Supervision Net."

On Thursday, Chongqing authorities said 10 more officials, almost all of them district-level Communist Party of China chiefs, governors and executives of state-owned enterprises (SOEs), had been removed from their posts for allegedly appearing in sex videos.

Chongqing police busted a criminal ring suspected of using secretly filmed sex videos to blackmail the officials, local authorities said Thursday.

The Chongqing Municipal Commission for Discipline Inspection found that the criminal ring had hired women to seduce local officials, covertly filmed their sexual acts and used the videos as tools of extortion to get government contracts.

Zhu told Xinhua that some officials featuring in the videos had not been punished and urged the city authorities to launch a thorough investigation.

He claimed to have seven videos, six from a source with the Chongqing municipal public security bureau, and one from a member of the criminal ring.

On Monday, Zhu rejected demands from police officers that he surrender the videos. He said he wanted to protect his source as he believed Chongqing police authorities wanted to use the videos in order to find out who the source is.

In November 2009, Wang Lijun, a former police chief of Chongqing, once organized a special team to investigate the scandal. However, officials in the videos were not punished and some even received promotion, Zhu said.

The source from the Chongqing municipal public security bureau was punished when Wang was the bureau director and he wanted to make the sex videos public to take revenge on Wang, he said.

Zhu said he might make public the other sex videos to help in the anti-corruption campaign in Chongqing.

He added that he had received death threats after making public the first video of Lei Zhengfu.