Guenter Hirsch wrote in a letter to ethics commission president Claudio Sulser that FIFA appeared unwilling to deal with growing problems.
The 67-year-old former president of Germany's highest appeals court said FIFA showed "no real interest" in trying to clean up the organization.
"The events of the past few weeks have raised and strengthened the impression that responsible persons in FIFA have no real interest in playing an active role in resolving, punishing and avoiding violations against ethic regulations of FIFA," Hirsch wrote in the letter, according to the German DPA news agency on Sunday.
FIFA officials were accused of bribe-taking and vote-trading before the World Cup host election last month.
The 2018 World Cup was awarded to Russia and the 2022 tournament to Qatar.
FIFA's ethics panel investigated and barred two of the 24-member executive committee members, Amos Adamu and Reynald Temarii, from voting based on evidence provided from an undercover sting by a British newspaper, The Sunday Times.
Adamu from Nigeria became the first FIFA official suspended for bribery and is serving a three-year ban from soccer duty.
Temarii, a FIFA vice president from Tahiti, was given a one-year ban for breaching rules on confidentiality and loyalty. Both men have said they will appeal their punishments.
Four former FIFA executive committee members _ Tunisia's Slim Aloulou, Amadou Diakite of Mali, Botswanan Ismail Bhamjee and Ahongalu Fusimalohi from Tonga _ were suspended for between two and four years after they advised undercover reporters how much to pay FIFA voters in bribes.
FIFA president Sepp Blatter has promised to ensure his organization is free of corruption after scandals surrounding the World Cup hosting votes and intends to establish a new committee with outside members to monitor the governing body.
The Swiss FIFA president is aiming to present the project to FIFA's congress of 208 national governing bodies in June, where he will stand for re-election seeking a fourth four-year term.