Tzipi Livni, the Israeli foreign minister, has called on Ehud Olmert, the acting prime minister, to stand down immediately due to corruption charges.

Livni made the call on Thursday after authorities announced that they would press charges against Olmert.

"The prime minister has to take a leave of absence, there's no other choice," Livni said at a meeting of the ruling Kadima party in the Tel Aviv satellite town of Petah Tikva.

"Israel cannot tolerate a situation where he is acting as prime minister after a decision to indict him. This is a moral test, this is a question of values and a practical test."

Israel's attorney general wants to try Olmert for alleged double billing of Jewish groups for trips abroad.

Olmert said in July that he would step down as prime minister and not contest parliamentary elections scheduled for February, to fight corruption allegations. He is currently head of a caretaker government

However, Livni has said that he should not wait untill the elections to resign.

His exit would allow Livni to become acting prime minister until the elections.

Livni became leader of the Kadima party in September after an internal election.

But she was unable to gather support of enough legislators to form a new ruling coalition, prompting February's early vote.