A Cathay Pacific flight bound for Australia was delayed for two hours at Chek Lap Kok airport yesterday because of an oil leak.
Four fire engines were dispatched as a precautionary measure while flight 163 waited for clearance.
The plane, an Airbus A330, was supposed to take off for Melbourne at 10.20am, but oil was seen leaking from its left wing as passengers were preparing to embark.
Another plane was brought in and the flight eventually took off at 12.12pm.
Cathay said there were 216 passengers on the flight.
"The airline is looking into the technical problem," a spokeswoman said.
A Fire Services Department spokesman said there were no casualties and firemen remained on standby until after the flight took off.
A Cathay Pacific pilot said it was fortunate the leakage was spotted.
"If it had not been detected and the plane had taken off, the fuel might have flowed to the engine and caught fire," he said.