Israeli justice officials Thursday said Olmert received fraudulent payments from New York philanthropist Morris Talansky while the prime minister served as the mayor of Jerusalem and industry minister in the 1990s.
Members of Olmert's Kadima party Sunday stood by him, saying he is presumed innocent, Ynetnews.com said.
"The prime minister, like any other citizen, has the right of innocence. He is innocent until proven guilty," said Transportation Minister Shaul Mofaz.
Olmert has denied breaking any laws and has said he would resign immediately if the investigation produced an indictment.