Leader of Israel's Labor Party, Amir Peretz, yesterday declared that his party would not vote in favour of the plan to annex the occupied West Bank, the Israel Broadcasting Corporation (Kan) reported.
He also said that he would exert as much effort as he can in order to undermine this plan or any other unilateral measure.
Peretz's remarks came in response to criticism following his party's decision to join a coalition government with Prime Minister Benjamin Netanyahu.
"The alternative was going to a fourth election," Peretz said, adding that this is the first time in Israel's recent history that the date on which Netanyahu will step down from office is known.
On Monday, Netanyahu and his centrist election rival Benny Gantz signed a deal to form a national emergency government, ending a year of unprecedented political deadlock.
The power-sharing agreement clinched after weeks of negotiations gave a clear end-date for the premiership of Netanyahu, Israel's longest-serving leader, who has become for many the face of the nation.