Sydney-bound Qantas flight from Queenstown diverted after suspected engine issue

A Sydney-bound Qantas flight from Queenstown in New Zealand has been forced to divert as footage taken shortly after take-off appears to show flames shooting out from one side of the plane.

A spokesperson for the airline confirmed flight QF122 from Queenstown had experienced an incident mid-flight on Saturday, saying it was a "suspected engine issue", and had to be diverted.

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

In footage provided to ABC News, the aircraft's left engine seems to be emitting flames.

The Boeing aircraft had left the alpine ski town just before 3:30pm and was scheduled to land at Kingsford Smith Airport at 4:50pm.

The national carrier told the ABC that the aircraft was cleared for a priority landing at Christchurch, and both engines remained operating throughout, with no engine shutdown or failure experienced.

Liam Aspinall was sitting with friends having a drink in Queenstown when he noticed the flames approaching from a distance.

"I noticed flames appearing to come off the thing as it was approaching us from afar," Mr Aspinall told ABC News.

Support is being provided to passengers, according to the Qantas spokesperson, in recognition of what "would have been a distressing experience".

Passengers are being offered accommodation and help with getting alternative flights.