Fifa is to investigate whether West Ham should have been docked points for breaching Premier League rules when signing  Carlos Tevez.

The Premier League has already fined the London club £5.5 million for using a "third party" when signing the Argentina international, but has refused to bow to pressure from other struggling Premiership clubs to dock the club points.

Sheffield United, who were relegated at the weekend after losing out to Wigan on goal difference, have said that they will pursue legal action against the Premier League.

On Sunday Tevez scored the crucial winner for the Hammers against champions Manchester United in Old Trafford, which kept them in the top flight for another season at the Blades' expense.

Sepp Blatter, president of Fifa, said the game's world governing body had the power to pass a final verdict on an independent commission's decision to fine West Ham.

Blatter told a media briefing in Zurich: "We will look at this - and not only if we are asked, we will do it anyway.

"We will ask for the file once it has been decided how and why the decision was made," he added. "If we feel something was wrong in this decision then we have to open our file."

Blatter said in terms of timescale a "decision would have to be taken immediately."

He added that according to Fifa's files the transfer of Tevez and his Argentinean team-mate Javier Mascherano, now of Liverpool, from Brazilian side Corinthians had complied with international transfer regulations.