A section of the bridge that weighed an estimated 3,000 tonnes collapsed onto the cargo ship, which had 20 people on board, when the accident occurred on Thursday, the Beijing News newspaper said.

Of the 20, 16 people were rescued but four remained missing. Nobody was on the bridge, which was being built in the port city of Ningbo in Zhejiang province, according to the Beijing News.

Local government offices and the rescue centre in Zhejiang could not immediately be reached for comment.

In August last year, a bridge under construction collapsed in central China, killing at least 29 people.

It crumbled as workers were removing steel scaffolding erected during the building work.

In June last year, a cargo vessel struck a bridge in southern China, killing nine people.

The Chinese government last year announced plans to fix or rebuild about 6,300 damaged or badly built bridges across the country by 2010.

The Ministry of Communications said that many bridges had been hastily built, leading to structural problems, amid the massive development rush in booming China. -- AFP