Passengers on a Thai Airways' flight from Bangkok to Brisbane have had an unscheduled stopover in Bali after an engine problem forced an emergency landing at Denpasar.

The Boeing 787-8 Dreamliner had been delayed three-hours in Bangkok and was a few hours into the flight when passengers noticed a change in the flight path information.

One of those on board, Paul Pluta, said he asked cabin crew what was going on and was eventually told an emergency landing was needed due to a faulty oil sensor.

Fuel was dumped prior to landing at Ngurah rai Airport early yesterday morning.

Mr Pluta said the landing felt "very hard" before the aircraft came to a stop.

"They normally say 'cabin crew arm the doors' before landing, but they didn't say that this time," he said.

"That means the safety shutes were ready to fire on a bad landing."

Inspections determined the right engine had an oil pressure issue.

The 264 passengers on board were accommodated in hotels while repairs were conducted on the 787.

A Thai Airways spokeswoman said the plane was scheduled to continue its journey to Brisbane this afternoon, ahead of an 11:30 p.m. landing - 36-hours after its original arrival time.

Mr Pluta was able to get on a Virgin Australia flight to get home more quickly.

Thai Airways was placed "on notice" by Australia's Civil Aviation Safety Authority last year following international concerns that led to bans on charter flights by the airline to China, Japan and South Korea.

Additional ramp inspections were conducted to evaluate the condition of the aircraft and documentation filled out by crew.

Respected aviation safety site, AirlineRatings.com awarded Thai Airways four stars out of seven in its most recent review.

The last major incident involving Thai Airways was at Guangzhou in China, when an A330 experienced a runway excursion causing extensive damage to the plane and tarmac. No one on board was seriously hurt.