Police have ruled out foul play in the road accident that killed Balakong assemblyperson Eddie Ng Tien Chee this morning.

Kajang police chief ACP Ahmad Dzaffir Mohd Yusoff said this was based on preliminary investigations into the 12.30am incident.

"Based on information from the investigating officer, there is no foul play involved," he said when met at the Police Training Centre in Cheras today.

Ahmad Dzaffir was responding to queries on claims that there was an oil spill at the scene where the accident had occurred, saying the spill had occurred after the crash.

"I was there at the scene after the incident. The oil spill happened afterwards," he said.

Ahmad Dzaffir said the initial investigation showed that Ng was trying to overtake a Myvi car on the middle lane, when the SUV he was driving hit the back of a lorry doing road cleaning on the right lane.

The driver of the Myvi escaped unhurt.

Ng was killed in the accident at Km11.7 of the Grand Saga Highway.

His death will trigger the second by-election in Selangor after the 14th general election.

The first, for the Sungai Kandis state seat, will be held on Aug 4 following the death of its assemblyperson Mat Shuhaimi Shafiei of PKR on July 2, due to lymphoma.