Olmert, in Paris for talks with Jacques Chirac, the French president, said that his plan "could not be stopped" and that it was the "most Israel is prepared to agree to".
The controversial plan proposes to unilaterally redraw Israel's borders with the Palestinians by 2010, if peace efforts remain stalled.
"I prefer to reach a negotiated settlement [with the Palestinians], but if that is not the case we will apply our plan," he told journalists after talks with the French leader.
Chirac, however, emphasised the need for talks to create two states living "side by side and in security" and said France would work to achieve this goal.
"This objective supposes a resumption of negotiations between Israel and the Palestinian Authority. France and the European Union are totally determined to contribute as much as possible to the building of this peace," Chirac said.
"I prefer to reach a negotiated settlement [with the Palestinians], but if that is not the case we will apply our plan"
Ehud Olmert, Israeli prime minister
Olmert responded that he would "make every effort" to resume negotiations with the Palestinians over a two-state solution, but reiterated that they must first end terrorism, respect agreements between the two sides and recognise Israel before negotiations can take place.
Olmert's France visit is the latest stop in his tour of countries in an attempt to gain support for his border plans, which have met with a mixed response from world leaders.
Last week, Olmert discussed the plan with Tony Blair, the UK prime minister, in London.
Some West Bank settlements
would go under Olmert's plan
Blair said he favoured a negotiation but added that talks could only resume if Israel's conditions were met, otherwise Israel could seek to "unlock" the situation.
In May, the US cautiously welcomed Olmert's plan, while Arab countries have rejected the proposals.
Under the plan, thousands of Israeli settlers would be removed from isolated West Bank settlements but other settlements would be reinforced.
The Palestinians have rejected the plan as an attempt by Israel to grab land.