SYDNEY — A Qantas flight landed safely at Sydney Airport Wednesday after a mayday alert was issued on approach.

"The 145 passengers onboard disembarked the aircraft normally," Qantas stated.

The airline said QF144 reported "an issue with one of its engines" over the Tasman Sea after departing Auckland, New Zealand on Wednesday afternoon.

The mayday alert was downgraded to a "possible assistance needed" alert before the flight landed at Sydney Airport (SYD) around 3:30 p.m. local time, the airline said.

The Boeing 737 was "about an hour from its destination" in Sydney when the alert was issued. The route between the countries' two largest cities usually takes about three and a half hours.

Fire, ambulance and police services were sent to the Sydney airport as a precaution, according to a representative for the airport.

Qantas engineers are now assessing the aircraft, the airline confirmed.

"While inflight engine shutdowns are rare, and would naturally be concerning for passengers, our pilots are trained to manage them safely and aircraft are designed to fly for an extended period on one engine," said an official statement from the airline.

Passengers told CNN affiliate 7NEWS they heard some disruptions on the flight; however, they couldn't tell what had caused it.

"I just heard a bang, and maybe a slight shudder, but that was it," one passenger said. "They were so professional about it and so calm about it."

"I noticed something, but it wasn't really recognizable," another passenger said.

No one on board was injured. — CNN