SINGAPORE - A Scoot flight to Singapore from Bangkok was delayed for more than 21 hours on Thursday, after the plane suffered a technical fault while still at Bangkok's Don Mueang International Airport.

Flight TZ301, which was supposed to touch down here at 11.55pm on Thursday, had already been boarded when passengers were told to disembark as the plane had experienced problems.

Scoot declined to reveal how many passengers were on the flight but it is understood its flights are typically about 80 per cent full. The flight had a capacity of 402 passengers. It will now arrive here on Friday at 9.10pm.

Passengers, who waited close to three hours on the plane before told to disembark, were irate and posted comments on Scoot's Facebook page, demanding updates to the situation.

"Flight from Bangkok delayed for 20 hours!!! Such a nightmare!!!! Now 300 passengers stuck in Don Mueang Airport," said Facebook user Ton Pongsathorn.

Meanwhile, family members of passengers on the flight were also waiting for updates.

Sales manager Ken Chong, 33, said he called Scoot's hotline multiple times but was unable to get an updated flight arrival time so he could pick his wife up from the airport.

"My wife told me they kept delaying the flight and pushing back the departure time," said Mr Chong, adding that service staff in Bangkok told his wife the delays were because the plane was waiting for fuel.

When contacted, a Scoot spokesman said the delay was because the aircraft suffered a technical issue which required a spare part to be flown to Bangkok from Singapore.

He declined to comment if passengers would be compensated.

"The aircraft had to be serviced and that caused a delay. Passengers were put up at the hotel, after the servicing was done, they were brought back to the airport," said the spokesman.

"We understand that it can be a frustrating delay for the passengers affected, but we seek their kind understanding on this as safety is the first priority for us."