One of the workers injured in the collapse of an uncompleted Tampines viaduct has taken a turn for the worse.

In a statement, a spokesman for Or Kim Peow Contractors (OKP), the main contractor of the project, said that Chinese national Gao Liqin, 49, underwent surgery at 7pm yesterday after his condition deteriorated earlier in the day.

Mr Gao, who has been in the intensive care unit (ICU) since the incident last week, is employed by Tongda Construction and Engineering, a sub-contractor on the project to build the viaduct, which links the Tampines Expressway to the Pan-Island Expressway.

The July 14 accident left one worker dead. Mr Gao and nine others injured were taken to Changi General Hospital (CGH).

Two of Mr Gao's family members arrived here yesterday, and OKP, which helped to make the travel arrangements, will continue to take care of their accommodation, transportation and other needs in Singapore.

Bangladeshi worker Barek Mohammed, 25, has been transferred out of the ICU to the high-dependency unit and his condition will be monitored closely, said the spokesman.

Of the injured, six remain warded in CGH. OKP said it will continue to cover the loss of income for all injured workers while they recover.

Mr Or Toh Wat, group managing director of OKP, said its top priority was to ensure the welfare of the injured and the family of the worker who died.

"OKP will also be providing all necessary assistance and support to the six family members of the deceased worker, the late Mr Chen Yinchuan, when they arrive in Singapore."