A top UN official has warned there would be "catastrophic consequences" if Israel expands its military operations in Gaza, after reports Israel's Prime Minister, Benjamin Netanyahu, is pushing for a total reoccupation of the strip.

Assistant Secretary General Miroslav Jenča told a meeting of the UN Security Council such a move would be "deeply alarming" if true, and could endanger the lives of Israeli hostages held by Hamas.

Israeli media reported that Netanyahu plans to meet with his security cabinet this week.

"The die has been cast. We're going for the full conquest of the Gaza Strip – and defeating Hamas," local journalists quote a senior Israeli official as saying.

Such a move still needs the approval of the security cabinet, which is due to meet Thursday. There are fears that a new escalation of the war in Gaza – where experts say that famine is unfolding – would put the lives of more Palestinians and about 20 living Israeli hostages at risk.