South Korean officials are launching an investigation into the cause of the fire that engulfed an Air Busan passenger plane while awaiting takeoff at Busan's Gimhae International Airport, with some eyewitness accounts leading to speculation that a portable power bank may have caused the blaze.

It is a month since the deadliest air disaster on South Korean soil when a Jeju Air plane coming from Bangkok crashed on Muan Airport's runway as it made an emergency belly landing, killing all but two of the 181 people and crew members on board.

An investigation into a fire that engulfed an Air Busan plane at a South Korean airport this week is being slowed by a large amount of fuel and oxygen still on board, an air crash investigation official told Reuters.