Adidas and Kia Motors have refused to join the likes of Coca-Cola and Visa in demanding the immediate resignation of FIFA President Sepp Blatter. He is being investigated by Swiss authorities but denies any wrongdoing.
German sportswear giant Adidas chose not to mention Blatter in statements made on Saturday.
"FIFA must implement fundamental changes for the sake of football," a spokesman told several news agencies on Saturday. "Therefore, the initiated reform process must continue quickly and transparently."
Adidas is a major soccer sponsor and has provided every match ball for FIFA World Cup matches since 1970.
South Korea's Kia Motors, which has sponsored FIFA with affiliate Hyundai since 1999, also refused to be drawn into the debate on FIFA's leadership.
"We at Kia do not have any comment at the present time regarding Sepp Blatter or our current FIFA sponsorship status," the South Korean firm said.
The statements came in response to a seemingly concerted effort on Friday by four other major sponsors of soccer's world governing body - Coca-Cola, Visa, Budweiser brewer Anheuser-Busch InBev and McDonald's - demanding Blatter step down immediately as FIFA's promised reform process lacked credibility.
Visa, which has a FIFA deal through the 2022 World Cup, said "no meaningful reform can be made under FIFA's existing leadership."
Anheuser-Busch InBev, which has sponsored FIFA since 1986, denounced Blatter's continued employment at FIFA as an "obstacle in the reform process."
Blatter appears determined to stay in power despite being investigated in Switzerland for allegedly undervaluing World Cup broadcasting contracts for the Caribbean sold to disgraced former FIFA Vice President Jack Warner in 2005.
Blatter, who has denied any wrongdoing, was also questioned over what's deemed a "disloyal payment" of 2 million Swiss francs (now $2.04 million) in 2011 from FIFA to the president of the governing body of European football - UEFA's President Michel Platini.
At the end of September, Blatter said he would not resign immediately. The 79-year-old is, however, due to step down at a FIFA extraordinary congress in February.
FIFA has been rocked by allegations of corruption for years. In May, the US Justice Department charged 14 FIFA officials with bribery in football deals worth more than $150 million dating back to 1991.
ng/sms (AP, dpa, AFP)