Zico, a hero of Brazilian teams of the late 1970s and early 1980s and former sports minister, declared he would enter the race.
"I feel I am capable. For sure, certain rules need to change," he told a press conference in Rio de Janeiro. "Much needs to change and much is going to happen"
Prince Ali bin al Hussein, who stood against Blatter in last month's election, has indicated he could also stand along with a former FIFA vice president Chung Mong-Joon of South Korea.
But UEFA president Michel Platini refused to discuss his plans at a Paris press conference to mark one year from the start of the European Championships in France. Platini only said it was a "good thing" the 2026 World Cup campaign had been halted. "There is no leadership at FIFA," he commented.
Wolfgang Niersbach, a Blatter critic, said the election should be held quickly.
"With all due respect for his life's work, Sepp Blatter does himself, and football as a whole, no favours by drawing out his resignation," Niersbach wrote in a letter to German clubs and regional associations.
"A new president must be chosen quickly at an extraordinary congress to represent a compelling new beginning."
He also called for "comprehensive reform" of the world body. "It must be our common goal to prevent unscrupulous people being enriched at the expense of football and tighter cash flows are needed."
