The embattled Uefa president, Michel Platini, has been backed by his home French football federation (the FFF) and the South American confederation Conmebol despite being embroiled in criminal investigations in Switzerland and suspended by Fifa.

Platini on Saturday lodged an appeal against his 90-day suspension from all football activities, which has dealt a fundamental blow to his candidacy for the Fifa presidency.

The appeals committee, chaired by the Bermudan Larry Mussenden, is expected to decide within eight days whether to overturn the suspension, imposed pending a full investigation. The Swiss attorney general, Michael Lauber, has opened criminal proceedings against Sepp Blatter over a £1,3m payment to Platini, which both men have said related to work Platini did at Fifa in 1998-2002. Platini has been questioned by Swiss prosecutors as “a person providing information”, a legal status which allows for the possibility of being charged in the future.

The Fifa ethics committee’s suspensions are designed to ensure that a full investigation can take place without any possibility of interference by those accused of wrongdoing. Platini filed his candidacy papers for president before he was suspended, but it is thought unlikely he could still stand if the suspension is not overturned, as he would need to pass a Fifa integrity process. The FFF said that if Mussenden’s committee does not overturn the suspension it will appeal against the decision to the court of arbitration for sport.

Conmebol, two of whose former presidents, Nicolás Leoz and Eugenio Figueredo, and two directors, Rafael Esquivel and José Maria Marin, are among the nine high-ranking Fifa officials indicted on corruption charges by the US department of justice, denounced the ban on Platini, calling it “untimely and disproportionate”.

Conmebol said in a statement: “The presumption of innocence is a fundamental right that has to be considered. Mr Platini has not been found guilty of any charge, therefore the provisional ban jeopardises the integrity of the electoral process … These are trying times that demand an integral reform of Fifa. [Conmebol] fully believes in Mr Platini’s capacity to lead Fifa and the football world towards a brighter future.”

The Fifa executive committee meeting later this month may discuss whether to delay the presidential election, which remains scheduled for 26 February, due to the still unfolding crisis.