China building collapse death toll now 10

At least 10 people have been killed when a building undergoing renovation collapsed in China's financial hub of Shanghai.

The roof of a building under renovation in Shanghai collapsed, trapping more than 20 workers. (AAP)

The death toll following a building accident in Shanghai has climbed to 10, state media reported Friday.

The roof of a building under renovation in central Shanghai collapsed on Thursday, trapping more than 20 workers, according to China's Ministry of Emergency Management.

Five people were initially reported to have been killed.

The rescue mission had ended by 1.45am on Friday ( 5.45am AEST), at which point rescuers had found 25 people, including 10 dead, state broadcaster CCTV said.

Authorities initially said the building was a Mercedes-Benz dealership, but they later referred to it as a factory.

More than 150 firefighters and 24 fire engines participated in the rescue operations.

Videos posted on Weibo showed a massive collapsed building and firefighters searching through the rubble.

The building was located in the residential Changning district in central Shanghai.