Singapore Airlines (SIA) has been forced to postpone plans for a thrice-weekly Singapore-Jakarta-Sydney service, which had been due to start on Nov 23, after being told that Soekarno-Hatta International Airport had to undergo runway maintenance.

The airline had earlier been given the green light for the new flights by the Indonesian authorities and secured landing-take off slots, and was already selling tickets.

"However, SIA has been informed by the Indonesian civil aviation authorities that they are now unable to approve the flights due to runway maintenance works at Jakarta's Soekarno-Hatta International Airport, which also affect other airlines," it said in a statement yesterday.

It is not clear how long the works will last and which other carriers are affected.

Apologising to customers for the inconvenience, SIA said it will contact those with confirmed bookings and make alternative flight arrangements for them. Those who wish to cancel their bookings will be given a full refund.

The airline declined to say how many customers were affected, but it is understood that a good number are Australia residents based in Jakarta who had made plans to return for the year-end holidays.

In response to media queries, the Civil Aviation Authority of Singapore (CAAS) said it hoped approval for the new service would be given as "soon as possible", highlighting how it benefits Jakarta, Sydney and Singapore.

"SIA's new service will enhance air connectivity between Singapore, Jakarta and Sydney, which will facilitate people and trade flows between these cities," CAAS said.

With the new service, the airline will have a total of 34 weekly flights between Singapore and Sydney, and 74 flights a week between Singapore and Jakarta.

Its launch of the new service would help SIA grow its footprint in a key market as it continues to battle aggressive rivals in the long-haul premium market.

The Sydney-Jakarta route is currently served by Australia's Qantas and Garuda Indonesia.

According to Sydney Airport, the number of passengers travelling between Indonesia and Sydney grew 13 per cent to 620,000 during the past year.

While the service delay is "disappointing", the impact for passengers is not expected to be significant, said Centre for Aviation analyst Brendan Sobie.

"It is only three weekly flights and SIA can re-accommodate the passengers via Singapore," he said.