Jetstar has denied a report that passengers were stranded on a tarmac in Hawaii without air-conditioning for four hours.

The Honolulu-to-Melbourne flight was due to leave this morning but had to be cancelled because of a mechanical problem.

Fairfax is reporting that passengers became ill after being forced to stay on board for four hours.

But a Jetstar spokesman says it was only two-and-a-half hours.

He says the air-conditioning was operating and passengers were offered water.

The flight has been delayed for 24 hours and all those affected have been offered overnight accommodation.