Two men were hurt in a chain collision involving four cars at the Woodlands Checkpoint in the early hours of yesterday.
The police said they were alerted to the accident at about 3.30am.
The two injured men were the drivers of two of the cars. The men, aged 32 and 51, were conscious when taken to Khoo Teck Puat Hospital.
The Singapore Civil Defence Force said the two men suffered minor injuries.
The Straits Times understands the accident involved three Singapore-registered cars and a Malaysian-registered car.
Police investigations are ongoing.
Photos and a video posted on road traffic Facebook page SG Road Vigilante show the wreckage.
How long the departure viaduct at the Woodlands Checkpoint was closed due to the accident.
It includes a black Subaru with a severely damaged front bumper and hood.
At least two other cars were crushed at the rear and the passenger doors were dented.
The accident led to a 1 1/2-hour closure of the departure viaduct at the Woodlands Checkpoint yesterday morning.
The Immigration and Checkpoints Authority (ICA) said in a Facebook post at 4am that the viaduct was temporarily closed, and advised motorists to drive carefully and listen to instructions from officers.
At 5am, ICA told motorists to use the Woodlands Crossing when departing Singapore.
The departure viaduct reopened at 5.30am, the authority subsequently said.
The accident comes a day after a fatal crash near the Woodlands Checkpoint.
Two men were killed and three others injured in the accident which happened at about 1am. It involved a trailer, a lorry and three motorcycles.
A 30-year-old trailer driver was arrested for suspected drink driving, while a 23-year-old lorry driver, who was one of the injured, was arrested for allegedly causing death by rash act.