Ten men were taken to hospital after an accident involving a lorry in Upper Bukit Timah Road on Saturday morning
The 35-year-old driver and nine passengers, understood to be foreign workers, were taken conscious to hospital, said the police.
The accident came just four days after another lorry carrying foreign workers collided with a stationary tipper truck on the Pan- Island Expressway early Tuesday morning. Two workers died in that incident and 15 were injured.
The police said they were alerted to Saturday's incident, near The Rail Mall, around 7.20am.
The men, who were aged between 26 and 50, were taken to Ng Teng Fong General Hospital, according to the Singapore Civil Defence Force.
The recent incidents renewed calls by migrant worker advocacy groups and members of the public to improve safety regulations for transporting foreign workers.
In response to queries from The Straits Times, a spokesman for Humanitarian Organisation for Migration Economics (Home) said: ''It is common sense that travelling in the back of a cargo lorry exposes passengers to greater risk of more severe injury in motor accidents.
''Given that strict road safety rules apply to all other road users, the fact that migrant workers are transported like cargo is inhumane and shameful.''
She added that Home has pressed the issue for years on the Manpower Ministry and in public.
Under the Road Traffic Act, employers can use lorries to ferry workers between their lodgings and workplaces.
Current safety regulations require drivers to stick to the road speed limit or 60kmh, whichever is lower, and workers on the carriage deck of lorries to be properly seated. Many suggest standards could be improved, for example, by making seat belts compulsory.
Ms Dipa Swaminathan, founder of ItsRainingRaincoats, said: ''The rest of us have been entitled to the safety of seat belts and there is indisputable evidence that seat belts can save lives... It is therefore unfair that migrant workers do not get such a basic safety feature.''
She added that a holistic solution addressing underlying issues for lorry drivers was also important, citing that several were migrant workers themselves who lacked adequate rest.
Others say workers should be taken to work by bus or van instead of in lorries.
As at yesterday, a Change.org petition for workers to be safely transported in buses or vans had gained more than 5,000 signatures.
Safety rules were last tightened in 2010, after two accidents in which foreign workers were flung from lorries. In one, three Chinese workers died after the overcrowded lorry they were in tipped over.
Public debate prompted the Government to bring forward the deadline for new regulations that required lorries to install canopies and higher side railings.
However, concerns about costs by industry stakeholders led the Land Transport Authority to review its previous plans in 2011 for lorry owners to double the minimum deck space to 8 sq ft for each seated worker.
Then president of the Singapore Contractors Association Ho Nyok Yong said smaller contractors might have to shoulder the financial burden of buying more vehicles or leasing buses to ferry workers.
Acknowledging these concerns, the Home spokesman said: ''But (at) what cost of a human life?''