Israel's chief negotiator Tzipi Livni on Monday defended a decision to meet Palestinian president Mahmud Abbas after peace talks collapsed, in a move that drew sharp criticism from ministers.

"I would like to remind everyone that the conflict isn't over," Justice Minister Tzipi Livni told her HaTnuah party at a weekly meeting, according to a statement.

"We're still here and the Palestinians are still here. Our interest is to resolve the conflict, and ignoring reality is not an option," she said.

Livni came under fire for holding talks in London with Abbas on Thursday, with Prime Minister Benjamin Netanyahu's office and ministers distancing themselves from the meeting, insisting it was private and did not signal official intention to resume talks.

She did tell US Secretary of State John Kerry in advance of her meeting with Abbas, but "the United States played no part in either arranging or participation in this meeting," State Department spokeswoman Jen Psaki told reporters.

"We continue to believe, as we've said, there's a door open to peace. It's up to the parties to determine that path."

Kerry had met separately with both Abbas and Livni in London last week.

Israel pulled out of the talks in mid-April, saying it would not negotiate with any Palestinian government supported by Hamas after the leadership in the West Bank signed a unity deal with the rival Islamist rulers of Gaza, who are committed to the destruction of the Jewish state.

"Ignoring the other side, not listening or talking, is irresponsible," Livni said.

"A resolution is best achieved through direct negotiations, but we can't ignore the agreement between Hamas and Fatah," she said, referring to Abbas's ruling party which dominates the West Bank-based Palestinian Authority.

"To all those politicians up in arms, I want to be clear -- we'll continue doing what we believe in, and that's what I did last week by meeting the president," Livni said.