Katsav, who is due to open the new session of parliament on Monday, is immune from prosecution as holder of the largely ceremonial post of president but could face impeachment by the Knesset.
"There is sufficient evidence indicating that in several cases... the president carried out acts of rape, forced sexual acts, sexual acts without consent and sexual harassment," police said in a statement.
"There is sufficient evidence indicating violation of the law banning wire-tapping by the president," they said following a meeting with investigators and Attorney General Menachem Mazuz.
Katsav, who has denied the allegations and says he is the victim of a "witch-hunt," could face between three and 16 years in prison if convicted, Israeli radio reported on Monday.
The charges are the most serious faced by an Israeli leader, although several other top figures, including former prime minister Ariel Sharon, have faced probes into allegations of corruption.
In recent weeks, police have investigated no fewer than 10 complaints of rape and sexual harassment by former Katsav employees during his presidency and as tourism minister.
The president has been questioned by police five times over allegations that he forced women employees to have sex with him by abusing his position of authority.
Police sources now say that an indictment could be filed in three or four of these cases.
Mazuz is expected to decide soon whether to file an indictment against Katsav, a married father of five who has rejected calls that he step down pending the investigation.
Katsav, a member of the right-wing Likud party, was elected president by MPs in July 2000 as a relative outsider who upset frontrunner Shimon Peres, an ex-premier and Nobel peace laureate.
The presidency is a largely symbolic post in Israel where political power is largely in the hands of the prime minister.
"Police have no legal authority to make any recommendations of this type," said Katsav's attorney Zion Amir.
"This is not the first time police have recommended the indictment of senior figures, including prime ministers, and those recommendations have all been rejected," he said.
The decision came on the eve of the opening of parliament's winter session, during which the president traditionally makes a speech.
Katsav said following the police announcement that he would attend Monday's ceremony but would not speak.
He has been under criminal investigation since July, when a senior female aide complained she was sexually harassed while working under him. The president filed a simultaneous complaint to the attorney general against the aide for extortion. But police said on Sunday that there was no substantial evidence to back accusations by Katsav's legal team that one of the complainants attempted to blackmail him over the rape allegations.
The Katsav case is the latest blow to Israel's leadership, with Prime Minister Ehud Olmert's government steering its way through public anger over failings of its 34-day war against Hizbullah in Lebanon.

Copyright AFP (Agence France-Presse), 2006