Former Israeli Foreign Minister Tzipi Livni says comments by her successor Avigdor Lieberman show Israel is not a partner for peace with the Palestinians.
Earlier, Mr Lieberman said Israel would not be bound by commitments made by the last government to start negotiations on creating a Palestinian state.
Ms Livni says the comments risk making Israel irrelevant and new Prime Minister Benjamin Netanyahu should repudiate them.
Mr Netanyahu has repeatedly declined to endorse United States-backed proposals for a two-state solution to the Israeli-Palestinian conflict.
On his first day at the Foreign Ministry, Mr Lieberman said the US-sponsored Annapolis declaration of 2007 "has no validity", confirming a shift in stance toward the Palestinians under Mr Netanyahu.
Mr Lieberman, a Soviet immigrant denounced as a racist by many Arabs, did stress, however, that Israel was obliged to follow the course charted by a US-backed peace "road map" of 2003.
That obliges Palestinian leaders to curb attacks on Israel before any negotiations on the final shape of a statehood deal take place.
Mr Lieberman was effectively confirming that Mr Netanyahu's new administration has withdrawn from its predecessors' commitment to negotiate on borders and questions such as the status of Jerusalem before the two sides are satisfied road map pledges are met.
The stance could push negotiations on statehood deep into the future. With Gaza in the hands of Hamas, many doubt Western-backed Palestinian leaders in the West Bank can meet Israeli security conditions for such talks in the near future.
A spokesman for Palestinian President Mahmoud Abbas said Mr Lieberman's comments threatened regional stability and urged the US to come out and make its opposition clear.
US President Barack Obama last week reaffirmed his commitment to the establishment of a Palestinian state. A spokesman for Mr Obama in London said: "We are committed to working vigorously for this two-state solution."
"We look forward to working with the new Israeli government and understand that we will have frank discussions," he added.
Corruption probe
Meanwhile, Mr Lieberman has been questioned by police for at least seven hours over corruption allegations.
Police say Mr Lieberman was questioned under caution on suspicion of bribery, money-laundering and breach of trust as part of a continuing investigation.
He was sworn in as foreign minister earlier in the week.
Mr Lieberman has previously denied any wrongdoing and says the corruption probe against him is politically motivated.
Mr Lieberman, an ultra-nationalist, is one of Israel's most outspoken politicians.
