Harry Kewell's $A12.26 million move to Liverpool has been referred to FIFA after it was revealed that his agent is not registered with soccer's international governing body.

The English Football Association sent the transfer documents to FIFA amid concerns at Bernie Mandic's role in negotiating the controversial deal.

Mandic, whose company MAX Sport collected $A4.9 million on the deal, does not have a FIFA agent's licence but his brother Nikola does.

Under FIFA regulations, only licensed agents can broker deals.

"The Football Association has today referred to FIFA documents relating to the transfer of Harry Kewell from Leeds United to Liverpool, on the back of the alleged involvement of a non-licensed agent in the transfer," FA media relations head Adrian Bevington told the FA website.

"Due to the international element of the transfer, and the fact that the FA has jurisdiction only over agents licensed by the FA, the matter therefore falls within the jurisdiction of the world governing body.

"The FA will provide any assistance that FIFA may require."

Mandic, who describes himself as Kewell's commercial manager, handled negotiations in the Socceroo's drawn-out transfer which was finally completed last week after six months of wrangling.

Mandic insisted no rules had been broken as his brother, who works for MAX Sport subsidiary Sports Corporation International, is a licensed agent.

"It's irrelevant because we have a FIFA-registered agent who's done all the negotiations on behalf of Harry with Liverpool and that's it. He's represented by my brother Nik and a lawyer named Chris Farnell," Mandic told AAP.

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