HOW long is too long to wait on hold? Thirty minutes? One hour? Three hours? Try 15 hours, 40 minutes and one second.

That's how long Adelaide businessman Andrew Kahn waited on hold on his mobile for Qantas from Wednesday night to yesterday morning.

"Outrageous" ... Adelaide businessman Andrew Kahn was put on hold on a call to Qantas for more than 15 hours. Credit:David Mariuz

Mr Kahn phoned Qantas at 7.22pm on Wednesday, trying to confirm his travel arrangements for a trip to New York on Sunday. He finally hung up at 11.01am yesterday, having not spoken to anyone.

A recorded message replayed constantly told him someone would speak with him ''as soon as possible''.