Okada, who coached Japan at the 1998 and 2010 World Cups, delivered sharp criticism in his farewell statement:
"As an athlete, I cannot accept this," said the 70-year-old.
Infantino has faced heavy criticism for, among other things, the scrapped proposal to sell shares in the World Cup.
The AFC's support for Infantino is significant: the federation represents 46 of FIFA's 211 member associations, which will vote when the president is elected in Rabat, Morocco, on March 18.
Infantino is seeking a fourth and final term, while the European Football Association (Uefa) seeks a rival candidate before the nomination deadline on November 18.
