"Only a centrist party can be a common denominator for all of the Zionist parties," she told a Tzofim (Israel Scouts) convention in Jerusalem.
Labor said the Kadima leader's statement was "delusory, especially considering the fact that she has already failed to establish a government even when all of the conditions were in her favor."
Likud called the Kadima leader's statement "ridiculous," adding "Livni and Kadima are going to lose the elections. (Likud Chairman) Benjamin Netanyahu will form the next government, which will be a broad unity government."
The FM warned Saturday night of a rift with the United States if a right-wing government is elected, as such a government would be perceived in Washington as a "peace refuser".
"(US President Barack) Obama's policy could be an opportunity for Israel. He wants to be involved and solve the conflict. His pressure will be directed at those who refuse this process, and Israel must choose whether it's on the side advancing a peace process or on the side of those refusing it, otherwise there will be an inevitable rift with the United States here," she said.
The Likud responded to the remarks by saying, "Livni is stressed because she knows she will be losing the elections in 16 days, so she's shooting at all directions and spreading a ridiculous spin, reflecting Livni and Kadima's great distress.
"(Likud Chairman Benjamin) Netanyahu knows the United States better than any other leader, will manage the relationship well and will know how to maintain the State of Israel's vital interests in the international arena."