Katsav had been scheduled to enter prison May 8 to serve a seven-year sentence, but the court granted a delay Tuesday following his appeal the previous day. The court set a May 11 date to hear a final appeal by Katsav's attorneys.
The conviction was handed down in the Tel Aviv District Court in December.
Katsav also was ordered to pay more than $28,000 to the rape victim and about $7,000 to the sexual assault victim. He was ordered to serve two years of probation after he is released from prison.
The 300-page appeal suggested that it would be undignified for Katsav to show up at the Supreme Court for his appeal in handcuffs, according to reports. The appeal also asked that "weighty consideration should be given to the fact that Katsav served as the president of the State and Israel's official representative at home and abroad."
The yearlong trial, which was closed to the public, ended with a guilty verdict on Dec. 30. Two years before the verdict was handed down, Katsav declined what was seen as a lenient plea bargain -- one that dropped the rape charges for lesser charges and likely would have left him with a suspended sentence -- saying that he wanted to clear his name in court.
Katsav, who immigrated to Israel from Iran in 1951, was elected president by the Knesset in 2000 in an upset of Shimon Peres. In 2007, Peres assumed the post following Katsav's resignation in the wake of the allegations shortly before the end of his term.