SINGAPORE, Sept 4, 2007 (AFP) - An online auction for seats on the first commercial flight of the super jumbo Airbus A380 is set to expand Tuesday, with seats on the return Sydney to Singapore leg up for bids, Singapore Airlines said.

The eBay online marketplace will begin offering seats at 10pm Sydney time (1200 GMT) for the October 26 flight, Singapore Airlines (SIA) said in a statement.

The flight will depart Sydney Kingsford Smith Airport at 4pm Sydney time and arrive in Singapore at 10pm Singapore time.

Seats on the first outbound flight from Singapore, on October 25, have been up for auction since August 27 and remain on the block, SIA said.

Bids close next Monday.

Stephen Forshaw, the airline's vice-president of public affairs, said Monday the auction was "exceeding our expectations across the board."

Singapore Airlines is set to be the first commercial airline to fly the double-decker A380, the world's biggest passenger plane.

Proceeds from the auction are to be divided equally between a Singapore charity, two childrens' hospitals in Sydney and the international relief agency Medecins Sans Frontieres.

SIA has committed to buy 19 A380s despite a series of delays that pushed back delivery from early last year.