Israel's recently ousted opposition leader Tzipi Livni plans to quit parliament on Tuesday but will remain active in politics, a confidant said.

Livni, who headed the Kadima Party for more than three years, was ousted as party leader several weeks ago by former defense minister Shaul Mofaz.

The confidant said Livni is to formally submit her resignation later in the day. He spoke on condition of anonymity pending the formal resignation.

Just a few years ago, Livni was one of the country's most popular politicians. A former foreign minister and chief negotiator with the Palestinians, she is well known in international circles and routinely shows up on lists of the world's most influential women.

But during her tenure as opposition leader, she faced heavy criticism for what was widely seen as an ineffective term.

There has been speculation she might join a new party headed by former TV personality Yair Lapid. An opinion poll published this week predicted that a party including Livni and Lapid could be the second largest party in parliament, behind Prime Minister Benjamin Netanyahu's Likud.

Netanyahu is widely expected to declare early elections soon.