THE HAGUE (AFP) - Dutch top flight outfit AZ 67 Alkmaar are to file a protest with FIFA over the contract which Brazilian Alfonso Alves has signed with English Premiership side Middlesbrough, insisting they have a claim on the player.

"We have a totally valid contract with Alves and we want to make that clear with FIFA. FIFA will then judge what should happen," said Alkmaar spokesman Klaas Wilting, who did not rule out legal action.

"The contract we have is clear: Alves must come to Alkmaar," he added, saying that "you can't sign two contracts".

Alves was playing for another Dutch side, Heerenveen, but was to have moved on to Alkmaar after signing a contract with them.

However, on Thursday, just before the transfer window closed, the Dutch Football Federation gave the player the green light to join Boro as he was no longer registered with Heerenveen, but not registered with Alkmaar either.

The forward has signed a four-year deal with Middlesbrough with media reports indicating a transfer fee of in the region of 16 million euros.