The driver of an airport engineering vehicle was left critically injured after a runway accident involving a private aircraft at the Sultan Abdul Aziz Shah Airport in Subang early this morning.

Investigations are underway to determine the cause of the 3.20am accident, according to Malaysian Airports Holdings Berhad (MAHB).

"We are saddened to inform that our staff member, who was the driver of the vehicle, was critically injured. 

"The staff member is currently undergoing surgery and we are ensuring that he receives the best medical care, as we pray for his recovery," its statement read.

"In the meantime, MAHB has formed an investigation team and is working closely with the Civil Aviation Authority of Malaysia to investigate the root cause of the accident.

"The Transport Ministry has also activated its Air Accident Investigation Bureau to carry out a thorough investigation of the incident."

MAHB added no passengers and cabin crew members were harmed during the incident.

According to the statement, the airport fire and rescue service team reported the incident upon arriving at the scene at 3.21am.

The accident and subsequent clearing of the debris resulted in the delay of several flights. MAHB stated that flight operations resumed at 9am.