A United Airlines flight from Melbourne to Los Angeles has been forced to make an emergency landing tonight after reports of smoke coming from the cockpit.

UA99 left Tullamarine Airport shortly after 1pm towards the west coast of the United States when something went wrong. It landed at La Tontouta International Airport at Noumea, the capital of New Caledonia, shortly after 4pm.

The Boeing 787-9 dreamliner was carrying 256 passengers and landed without any issues.

Passenger Nathan Lanier shared pictures of the aircraft on the runway three hours from Melbourne.

“Didn’t expect to end our trip in New Caledonia but want to commend the Captain and his crew of UA99 for a calm and professional emergency diversion,” he wrote.

Didn’t expect to end our trip in New Caledonia but want to commend the Captain and his crew of UA99 for a calm and professional emergency diversion @united - 🙏🏻 pic.twitter.com/Fa8kSRqa0P — Nathan Lanier (@treehousenate) March 25, 2019

A United Airlines spokesperson said they were on hand to assist passengers with whatever they needed.

All passengers are expected to spend the night in Noumea.

United Airlines has been approached for comment.

The emergency landing comes 15 days after an Ethiopian Airlines plane crashed on March 10 killing all 157 people on board.

The Boeing 737 MAX 8 was the second of its kind to be involved in a similar incident. A Lion Air plane carrying 189 people crashed in Indonesia in October, killing everyone on board.