A Sydney-bound Qantas flight has been forced to divert due to a suspected engine issue shortly after take-off from Queenstown on Saturday afternoon.

QF-122, a Boeing 737, was flying over New Zealand’s South Island when flames began bursting from the left engine, accompanied by repeated loud bangs that echoed across the valley below.

Queenstown locals on the ground heard the aircraft in distress as it flew overhead.

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“It did like maybe six or seven flame bursts and loud bangs,” witness Campbell Longmire said.

“It really echoed around the valley, so it was very loud. Everyone ran out onto their balconies and went to go look at it,” Daniel Longmire said.

It is understood the aircraft landed safely and normally in Christchurch.

“One of our flights to Sydney experienced a suspected engine issue after take-off from Queenstown this afternoon and the aircraft diverted to Christchurch,” a Qantas spokesperson said.

“Our pilots are highly trained to manage situations like this and the aircraft landed safely.

Flames blast from the plane. Credit: Supplied

The FlightRadar image showing the flight path. Credit: Supplied

The Qantas flight coming in to land at Christchurch. Credit: Kelly Henderson

“We know this would have been a distressing experience for passengers and will be contacting all customers to provide support.”

A Civil Aviation Authority of New Zealand spokesperson said it is aware of the Qantas flight incident, blaming a bird strike for the chaos.

“The flight departed Queenstown Airport bound for Sydney and experienced an engine issue after take-off,” it said.

“The aircraft subsequently diverted to Christchurch and has landed safely.”

Daniel Longmire said they were left shaken by what they saw.

“We were kind of just in shock, really. We were all a bit shaken. We didn’t know what was happening,” he said.

“You don’t see stuff like that every day. So, yeah, just kind of taken back, really.”

It is understood that customers on the plane will be provided accommodation and directed on to alternate flights.