Jetstar's worst problem on the Phuket route involved a double-delay flight that ended up costing the airline an estimated $1 million earlier this year. Eventually, an empty rescue aircraft had to be sent to Phuket from Australia.
Flight JQ 28, travelling from Phuket to Sydney early today, made the unscheduled Singapore stop after its pilots discovered a problem with the plane's auto-piloting system soon after takeoff.
A Jetstar spokesman told ABC that the 288 passengers have been offered accommodation in Singapore and booked onto other flights.
Jetstar now operates more flights from Singapore. The spokesman added that Jetstar hopes to send the delayed Phuket passengers on their way to Sydney within the next 48 hours.
The incident comes on a day when Jetstar has been acknowledged as the second-largest international airline operating to and from Australia, according to latest government figures.
The low cost carrier saw its share of international traffic increase 0.4 percentage points to 8.9 percent in August, eclipsing Air New Zealand (8.6 percent) and Singapore Airlines (8.6 percent). Both Jetstar rivals saw their share fall.
Australian pasengers to Phuket form an increasingly important part of Phuket's tourism market, with Jetstar providing most services.