Tens of thousands of passengers have been stranded by cancellations and major delays, as a one-day strike hits Australian airline Qantas.

The 12-hour strike, which will affect domestic and international flights, was called by the Australian Services Union (ASU) after pay negotiations with the airline failed on Monday.

Qantas said nearly 40,000 passengers would be affected by the strike on Friday with Sydney, the country's busiest airport, facing the worst disruption.

Friday is traditionally one of the busiest days of the week, and Qantas has been picking up extra flights since the collapse of rival Ansett earlier this year.

Internal dispute

The 6,000 ASU members taking part in the strike are demanding a 10% pay rise over two years and have rejected Qantas' offer of a 6% rise plus a 3-4% one-off bonus.

Three other unions representing Qantas staff have accepted the offer.

Qantas, which is backed by Australia's conservative government, said it could not give higher rises because of the difficulties in the aviation industry since the terrorist attacks of 11 September.

But the ASU claims the airline is not returning enough of its profits back to staff.

A long wait ahead

Qantas cancelled 22 domestic flights from Sydney and all of its flights from Canberra on Friday, with the majority of other flights subject to long delays.

The ASU members were mainly baggage handlers, check-in and clerical staff, and some engineers and maintenance workers.

Their strike meant pilots and airline managers were having to staff the check-in desks.