Pakistan International Airlines has said it is investigating reports that more passengers than the maximum allowed had travelled on an international flight, adding that it had launched disciplinary measures against the crew.

A PIA spokesman denied a newspaper report that seven extra passengers were forced to stand for the three-hour flight from Karachi to Medina in Saudi Arabia on 20 January.

“It is not possible for anyone to travel like that in an aircraft, regardless of the duration of the flight,” Danyal Gillani said.

A pilot and two other crew members were being disciplined, he said.

People with handwritten boarding cards scrambled for seats as the Boeing 777 taxied for takeoff on 20 January, according to the report in Pakistani newspaper Dawn.

Although the plane was allowed to carry 409 passengers, there were 416 onboard flight PK743 to Medina, the report said.

The official computerised list of passengers did not mention the extra travellers.

Carrying additional passengers on a plane is a serious breach of safety regulations. Those without seats would not have oxygen masks and might cause congestion if the aircraft needed to be evacuated.

The flight’s captain, Anwar Adil, told Dawn he only learned about the extra passengers after takeoff, by which point it was too late to turn around as this would have meant dumping fuel in order to land safely.

“I had already left and the senior purser [cabin crew] did not point out extra passengers before closing the aircraft door. Therefore, after takeoff, immediate landing back in Karachi was not possible,” he said.