On Thursday, addressing fundraisers from the United States and the European Union in Jerusalem, Olmert played down the planned conference, saying no dramatic breakthrough was expected at the meeting, scheduled for November or December in Annapolis, Maryland.
He also suggested the conference may not even take place.
"If all goes well, hopefully we will meet in Annapolis, [but] Annapolis is not made to be the event for the declaration of peace," he said.
The peace conference is expected to result in a framework agreement outlining the principles for a peace settlement. The talks will be closed to the press.
Major differences remain between the Israelis and Palestinians over the planned deal. The Palestinian side wants a detailed agreement specifying each party's commitment on key points, such as future borders, the status of Jerusalem, Palestinian refugees, and Israeli settlements. They are also seeking a timeline for Palestinian statehood. However, Tel Aviv has said it expects a more general guideline without binding commitments.
Olmert earlier said he regarded the meeting as a sign of international support for talks on creating a Palestinian state.
Negotiations on a peace settlement between Israelis and Palestinians were resumed when Abbas broke with Hamas following the Islamists' takeover of the Gaza Strip in June, which left Abbas and his Fatah forces in control of only the West Bank.
The United States has encouraged Arab states to attend the conference, but many of the countries remain skeptical, and have demanded clearer details of the conference goals.
Hamas, which has not been invited to the conference, called on all Arab countries to boycott the event, a position echoed by Iranian spiritual leader Ayatollah Ali Khamenei.
On Thursday, Israeli Defense Minister Ehud Barak approved a set of sanctions against the Gaza Strip, where militants continue to fire rockets into Israel. The measures include cuts in electricity and fuel supplies. Power is to be temporarily shut down immediately after any rocket attacks.
