Two box vans overturned on the North-South Expressway (NSE) in Perak on Friday morning, completely blocking all northbound lanes and causing a 1.7km traffic jam.
The Malaysian Highway Authority (LLM) said the crash occurred at KM257.7, on the stretch between the Menora Tunnel and Kuala Kangsar.
As of 9.18am, northbound traffic had come to a complete standstill following the incident.
It was not immediately known whether anyone was injured or killed in the crash.
Emergency response teams and recovery vehicles have been deployed to the scene to clear the overturned vans and reopen the affected lanes.
Northbound motorists have been advised to expect significant delays and exercise caution when approaching the area.
Motorists are also encouraged to consider alternative routes where possible to avoid the congestion.
