Five construction workers were killed and one person was injured in a tunnel collapse in South China's Guangxi Zhuang autonomous region on Wednesday.

The accident occurred around 3:30 am at Duoxian Tunnel on the Baise-Jingxi Expressway in Debao county, authorities said. The tunnel was under construction.

Rescuers work at the construction site of Duoxian Tunnel after it collapsed, on the Baise-Jingxi Expressway in Debao county, the Guangxi Zhuang autonomous region, on Wednesday. The accident killed five workers and injured one. Wei Zhi / China News Service

Seven workers were at the construction site when the cave-in occurred. One of them, Yang Junhua, escaped in time and informed the construction company.

The others were buried in the rubble, according to a statement from the rescue service headquarters.

Authorities arranged a rescue team made up of officials from the safety administration, transportation and medical departments after receiving an emergency call, said Tan Weifeng, a spokesman for the Baise city government, which administrates Debao.

At 11 am on Wednesday, the bodies of five workers were found, and Wang Ji, a 20-year-old migrant worker from neighboring Guizhou province, was taken to a hospital in Debao.

According to a statement from the Baise government, four of the victims were migrant workers from Guizhou, and the other was from East China's Fujian province.

The rescue work was completed on Wednesday, and the relief and compensation process will start for families of victims, Tan said.

An investigation team has been set up to probe the accident.

The expressway, which links Baise and Jingxi counties, was developed by the Guangxi Transport Investment Group. Calls to the company and its chairman went unanswered on Wednesday.

The expressway has a total length of 134 km, and the investment for the construction was 6.67 billion yuan ($1.06 billion), local newspaper Nanguo Morning News reported.

Construction started in September 2009 and was scheduled for completion this year. The expressway runs through mountainous areas, and the construction involved many bridges and tunnels, the newspaper said.

According to the original plan, the construction of the expressway would have been launched in 2020. But considering the economic development of the region, the government started in advance, Yu Changwen, chairman of Guangxi Transport Investment Group, was quoted as saying in a report from Nanguo Morning News in 2009.

A news conference was held by the Baise government on Wednesday, calling for an investigation and rectifying safety problems in construction sites of the Baise-Jingxi Expressway.

It is not known when construction work on the collapsed tunnel will resume, Tan said.

Huang Feifei in Nanning contributed to this story.

jinhaixing@chinadaily.com.cn