A Singapore Airlines flight to Wellington was cancelled yesterday after a pilot failed an alcohol test.

Singapore Airlines spokesman Karl Schubert said flight SQ247 from Melbourne to Wellington was cancelled due to an operating crew member being deemed unfit to fly.

"The Civil Aviation Safety Authority (CASA) officials undertook a random drug and alcohol test of all crew prior to them starting their pre-flight checks.

"The pilot in question did not pass the test due to having a higher than suitable blood alcohol limit," he said.

"The pilot in question was stood down and has been suspended from all duties effective immediately.

"He has returned to Singapore where a full investigation will be undertaken. We will also work closely with the Australian and Singaporean authorities to ensure they are supplied the information they require."

The incident meant the plane could not get to Wellington and its return flight to Melbourne was also cancelled.

Twitter user Muteki iikun was supposed to be a passenger on the flight and posted that he was going to miss Saturday night's All Blacks-Springboks test in Wellington as a result.

"@SingaporeAir care to try to explain why your captain (ie most experienced person on the aircraft) of SQ247 waits until boarding time to decide they're too ill/drunk to fly?," he Tweeted.

Schubert said Singapore Airlines apologised to those affected by the cancellation of these flights, however, the safety of their customers and crew is their highest priority.

"We have worked with customers whose travel was inconvenienced to find suitable alternate travel arrangements as quickly as possible," he said.

@SingaporeAir care to try to explain why your captain (ie most experienced person on the aircraft) of SQ247 waits until boarding time to decide they’re too ill/drunk to fly? Will miss the 1st #allblacks #rugby match I bought tickets for and flew to WLG from NRT to see😭 #sad

— Muteki iikun (@M_iikun) September 15, 2018