Sydney - Up to 40 people have injuries after a Qantas jet flying from Singapore to Perth experienced mid-air turbulence, West Australian police said Tuesday.

The Airbus A320 carrying more than 300 people made an emergency landing at Learmonth Airport near Exmouth on Australia's west coast.

The Australian Transport Safety Bureau (ATSB) said Flight QF72 had experienced a "sudden in-flight upset" while cruising in "level flight."

"The crew declared a mayday and diverted the aircraft to Learmonth, near Exmouth in WA, where it landed without further incident," the ATSB statement concluded.

Sergeant Greg Lambert told Australia's AAP news agency that the plane landed safely after making a mayday call.

"It's understood up to 40 people were injured during a mid-air incident," Lambert said.

Emergency services and medical staff boarded the Qantas aircraft to take the more serious cases to hospital. Ten passengers are believed to have lacerations and broken bones and the rest have minor injuries.

Ambulances from Exmouth hospital were at the airport. Qantas sent a jet to Learmonth so passengers could complete the journey to Perth. The Royal Flying Doctor Services sent paramedics in two planes to Learmonth.