Sepp Blatter has been urged to "stop flirting with power" by FIFA's Audit and Compliance Comittee chairman Domenico Scala.
On June 2, Blatter announced he would step aside as FIFA president - just four days after winning re-election for a fifth term of office - amid a scandal that saw nine past and present FIFA officials named among 14 people indicted on charges of racketeering conspiracy and corruption.
However, Blatter fuelled speculation that he may stand for the presidency again when he said earlier this week: "I have not resigned, rather I am offering my mandate at an extraordinary congress."
An interview with Blatter, published by Swiss newspaper Walliser Bote on Saturday, dampened those suggestions, though, with the 79-year-old saying: "I am not a candidate, but the elected president" and claiming the decision to leave FIFA was "liberating".
Scala, who will oversee the next FIFA presidential election that is expected to take place in early 2016, has now called on Blatter to stick by his original decision.
"The times of flirting with power are definitely gone," Scala said in a statement.
"I call on all concerned, including Mr. Blatter, to endorse in the interest of the reforms unequivocally the announced changing of the guard at the top of FIFA."
FIFA's Executive Committee is set to choose an election date at a meeting on July 20.
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