Scottish champions Celtic insisted yesterday they would not pay an outstanding £2.1 million demanded by Croatia Zagreb for the transfer of striker Mark Viduka.

The Glasgow club has handed evidence to world soccer's governing body FIFA outlining why they refuse to honour the Australian international's initial contract.

Viduka disappeared for five weeks after joining Celtic for £3 million two months ago. He has yet to play for the league champions.

FIFA had set a deadline of midnight yesterday for settling the bill, following Celtic's decision to pay only £900,000 to the Croatian champions.

A Celtic spokesman said: "We are sending a submission, as requested, and the matter is now in the hands of FIFA, which we feel is in everyone's best interests.

"We will be offering them (FIFA) a full disclosure and our co-operation with the aim of resolving matters to the satisfaction of all parties concerned."

Viduka claims he had an agreement with Croatia Zagreb for half the fee (£1.5 million) while his old Australian club, Melbourne Knights, say they are due £600,000 as their share of the deal.

It has been claimed in Scottish newspapers that Viduka's sudden departure to his Melbourne home on December 6th - citing depression - came after he discovered Zagreb had told Celtic that the player was waiving his rights to any money from the transfer.