The row, which dates back to Sion's expulsion from the Europa League in September for signing players while under a transfer embargo, has seen FIFA ask the Swiss Football Association to take action against the club.
On December 17 FIFA asked for Sion to be docked domestic points they won while fielding the players deemed to be ineligible for action and said if nothing was done by January 14 all Swiss national and club sides would be banned from UEFA and FIFA competition. But, in a statement released on their official website, www.fc-sion.ch, the Swiss club said on Thursday: "FC Sion has now filed a criminal complaint against executive members of the committee of FIFA after the threat to exclude the Helvetic Federation and clubs affiliated to it."
The statement continued: "The complaint was sent to the prosecutor in Zurich. It is directed against anyone who participated or contributed to the decision of the FIFA."
As things stand, that would affect Basle, who knocked Manchester United out of the Champions League and are due to face Bayern Munich in February.
The Swiss club were put under a transfer embargo over the signing of Egyptian goalkeeper Essam El Hadary, but proceeded to sign six players in the summer.
Sion then fielded five of the six players during the Europa League play-off tie against Celtic earlier this year and were kicked out of the competition as a result, with UEFA's decision to expel them upheld by the Court of Arbitration for Sport.
FIFA could not be contacted on Thursday evening.
Source: PA
Source: PA