Kadima chairman Shaul Mofaz officially became the new opposition leader Monday evening, after Kadima quick the coalition earlier in the week over differences in replacing the Tal Law.
Knesset speaker Reuven Rivlin made the announcement following a failed no confidence vote in the Knesset plenum.
Speaking after his ascension to the role for the second time this year, Mofaz vowed to defeat Prime Minister's bill to replace the Tal Law, which he said neither the public nor the High Court of Justice would accept.
He also accused Netanyahu of "never missing an opportunity to miss an opportunity," saying "what you can put off until tomorrow, you put off for two days."
"You've built a house of cards and the cards have collapsed on you," Mofaz added.