Passengers aboard a Qantas flight from Singapore to Perth suffered fractures and lacerations following a “sudden change in altitude”, the airline says.

Flight QF72 was forced to land at Learmonth in Western Australia on Tuesday afternoon after a mayday call.

“Emergency services, including medical attendants, met the aircraft on landing,” a statement from the airline said.

It said a number of passengers and crew had sustained injuries, including “fractures and lacerations”.

Qantas said there were no details available at this stage as to what caused the altitude change.

Police said up to 40 people were injured in the incident.

WA police Sergeant Greg Lambert said 10 passengers were taken to Exmouth Regional Hospital with injuries described as “quite serious”.

The Airbus A320 was carrying more than 300 people, he said.

“It is understood up to 40 people were injured during a mid-air incident,” Sgt Lambert said earlier.

He said Qantas had activated its passenger welfare plan and sent two aircraft to Learmonth to take passengers to their final destination in Perth.

The flight, operated by an A330-300 aircraft had 303 passengers and 10 crew on board, Qantas said in its statement.

An eyewitness said emergency vehicles and ambulances had surrounded the aircraft.

It landed safely at 1.35pm (WST).

The Civil Aviation Safety Authority said it had received an early report on the incident.