The Premier League and the Football Association are to launch a fresh inquiry into West Ham's conduct over the Carlos Tevez affair.

The new investigation, into West Ham's dealings with the striker's representatives after the club had initially been fined £5.5million for breaching league rules over third-party agreements, will be conducted jointly by the FA and the Premier League.

It follows the findings of an arbitration tribunal in favour of Sheffield United and against West Ham last year which decided Tevez should not have been able to play for the Hammers at the end of the 2006-07 season.

A joint statement said: "The Premier League and the FA are to institute a joint inquiry into the views expressed by the Independent Arbitral Tribunal chaired by Lord Griffiths in September 2008, which dealt with a compensation claim by Sheffield United against West Ham United brought under FA Rules.

"The joint inquiry will examine whether the conduct of West Ham United immediately after the Independent Disciplinary Commission's decision of 27 April 2007 amounted to further breaches of Premier League or FA Rules."

The inquiry means West Ham or individuals could face further disciplinary action but say they have nothing to hide from the new investigation.

The arbitration tribunal heard evidence from lawyer Graham Shear, solicitor for Tevez's agent Kia Joorabchian, that West Ham chief executive Scott Duxbury provided verbal assurances that the third party agreement still existed despite having informed the Premier League that the agreement had been terminated.

The Tribunal ruled: "If the Premier League had known what Mr Duxbury for West Ham was saying to Mr Joorabchian's solicitor following the commission decision, we are confident that the Premier League would have suspended Mr Tevez's registration as a West Ham player.

"We have no doubt that those [Tevez's] services were worth at least three points to West Ham over the season and were what made the difference between West Ham remaining in the Premiership and being relegated at the end of the season."

After being told the agreement had been terminated, the Premier League had then allowed Tevez to play for the Hammers in the crucial relegation battle that led to Sheffield United's eventual drop out of the top flight.

The Blades are claiming up to £50million in compensation from West Ham as a result.