Chinese authorities have arrested a local government official and a businessman suspected of sexually assaulting a woman at a business gathering, in a case that has sparked outrage in the country.

The woman was allegedly assaulted at a karaoke bar in Hangzhou after an official dinner involving executives from several companies and officials.

Local authorities said an investigation had found the woman was sexually assaulted by both men, adding that she had been pushed to the ground by one of them, causing injuries to her lower back.

Both suspects in the case have been dismissed from their positions, the statement added.

Sexual misconduct at drinks events is not unheard of in China, but arrests in such cases - particularly involving public officials - is less common.

In this case, the victim's injuries and the alleged involvement of a senior official and business executive from a state-owned company have fuelled public anger over what they see as an abuse of power in a workplace hierarchy.

It has been trending heavily on local social media platforms. The case was featured in seven of Weibo's top 50 trending topics on Wednesday.

The story generated even more attention after authorities released their findings.

One related topic received more than 68 million views, while several others received one to six million views each.

"Going to a drinks gathering does not mean consenting to be harmed, and drinking alcohol does not mean voluntarily consenting to abuse," one comment on Weibo read.

Many of the social media conversations have also talked about what is known as China's "drinking table culture" - especially because of reports that the woman was asked to drink heavily before allegedly being taken to the karaoke lounge.

"What is the rationale behind having women accompany men in drinking? Hopefully this practice can be eliminated," another comment said.

A comment piece in China Women's News said just dealing with the individuals involved would not be enough.

It said there was a need to define the "boundaries of business interactions through institutional measures, cutting off the grey areas where power becomes entangled with social obligations".