At least seven people were killed and four others suffered injuries after a gas poisoning incident at a biotechnology firm in eastern China, Xinhua news agency reported on Sunday.

The incident took place on Saturday afternoon at the Weifang Jinshi company in Shandong province, the news agency quoted emergency officials as saying.

Rescue workers had been deployed to aid the survivors and investigations are continuing, local authorities said.

"Those who sustained injuries are currently in stable conditions," Xinhua reported, citing the local emergency management bureau in Shouguang City, about 380 kilometres southeast of the capital Beijing. (AFP)