Passengers on a flight from the United States to Australia endured an even longer journey than they were expecting when their plane was diverted and then spent eight hours waiting on the tarmac, reports said Saturday.

Travellers on United Airlines flight UA863, with a scheduled flight time of just over 15 hours, found themselves stranded at Canberra airport on Friday because debris on the runway had prevented their plane from landing as planned in Sydney.

They could not be processed by immigration and the crew had worked too many hours to continue flying, reports said.

'Runway debris hijacks landing', said Sydney's Daily Telegraph in its report Saturday on the ordeal endured by more than 200 passengers who had flown from San Francisco on the Boeing 777.

The aircraft was diverted to Canberra and arrived at about 9:00 am local time but passengers were unable to disembark, the paper said.

The airport said that it could have made customs officers available had they been requested.

"We would've been open to that possibility but we didn't get the request from United," a spokeswoman told the Daily Telegraph. "They've elected to keep their passengers onboard."

After four hours on the ground, passengers were allowed onto the tarmac at Canberra, to get fresh air and stretch their legs without formally clearing the border.

The plane then left Canberra at about 5:00pm, and landed safely in Sydney, the Australian Broadcasting Corporation said, reporting that some passengers who had been on a connecting flight from New York had been by this stage been travelling for 30 hours.

Passenger David De Felice told the ABC the airline staff had managed the situation well.

"It's been a long day... I'm very sunburnt from being on the tarmac for four hours this afternoon," he said.

"We're good, the crew was good. They took good care of us, despite the situation."

Another passenger, Fabio Calabria appeared to have a sense of humour about the lengthy delay, which he said would make "one hell of a 'remember when' story".

"One positive is that I got fantastic value on this flight if u look at hrs spent in this seat," he tweeted.