Qantas has defended the ticket prices for seats on extra flights which have been made available to Western Australians travelling to Melbourne for next weekend's AFL grand final.

The airline today released an additional 4,200 seats on 24 extra flights from Perth to Melbourne between Tuesday and Saturday.

The least expensive ticket costs more than $650 one way, while others are more than $1,000.

Qantas regional manager for Western Australia, Ian Gay, says the high prices are due to the airline having to fly empty planes one way.

"To fly those aeroplanes four-and-a-half hours empty, to get them here to take the fans to Melbourne, there's a cost associated with that, so that's reflected in the high fares. I suppose that's what I'd ask people to understand," he said.

"I think you've just got to think about it for a little bit. These 24 extra flights will fly over here almost empty and take back a full load, so we'll average 50 per cent for the round trip." (Australian dollar is the currency used in this report)