KUALA LUMPUR, Dec 24 — Deputy Transport Minister Datuk Ab Aziz Kaprawi told the Road Transport Department (JPJ) today to work with traffic police and PLUS Malaysia in investigations on the cause of a bus accident in Muar that left 14 dead.

Ab Aziz also said he has requested JPJ authorities to make careful checks on express buses and to monitor the health of bus drivers.

"For road users, this is a reminder to us all to be more careful in our driving,” he posted on Facebook.

An express bus by Alisan Golden Coach plunged into a ravine along the North-South Expressway, which is run by toll expressway operator PLUS, in Muar in the wee hours of the morning en route to Kuala Lumpur from Johor Baru.

The Johor accident, the worst involving buses since the 2013 Genting Highlands crash that killed 37 people, had 14 fatalities comprising six men, seven women and a baby girl, including the driver.

The remaining 16 passengers were injured and reportedly in varying conditions.

Muar police reportedly said the bus driver was believed to have been speeding.