Shanghai has sacked three metro employees after a collision between two trains blamed on human error injured more than 280 people last month, the official Xinhua news agency said Thursday.

Two workers involved in the operation of the line where the accident happened and another from the subway operator Shanghai Metro Company were dismissed while another nine were also punished, the report said.

It gave no details of the other penalties.

The September accident fuelled doubts over the safety of China's rapidly developing transport network and came after a high-speed train crash in the eastern city of Wenzhou killed at least 40 people in July.

The Shanghai Metro Company has said errors by its staff played a role in the accident though it also blamed equipment failure, saying a loss of power caused the signalling system to fail and forced drivers to operate trains manually.

Xinhua quoted the accident investigation team as saying the crash was caused by human error.

Employees, who were communicating by phone after the signalling failure, neglected to verify the positions of the trains and failed to check whether the line was clear, causing one train to rear-end another, it said.

The metro operator initially placed the blame solely on a signalling system manufactured by Chinese-French joint venture CASCO Signal. The company has denied its products caused the crash.

CASCO is a venture between French transport and power giant Alstom and state-owned China Railway Signal & Communication Corp.

Alstom has also denied the venture supplied the signalling equipment implicated in the Wenzhou crash, as has been reported in Chinese media.