Israel's Labour party is to support a motion to dissolve parliament that could bring down embattled Prime Minister Ehud Olmert's government.

The bill will have its first reading on Wednesday. It would have to be put to a further two parliamentary votes before it can be passed.

Mr Olmert is under investigation for alleged corruption and Mr Barak has previously called for his resignation.

The Labour party is Mr Olmert's main coalition ally.

Mr Olmert, leader of the Kadima party, is being investigated over hundreds of thousands of dollars given to him by a US fundraiser in the years before he became prime minister.

He denies wrongdoing and has not been charged. He has also said he will not resign unless he is indicted.

Earlier this month, Mr Olmert ordered his Kadima party to prepare for a primary election that could see him replaced as its leader.

The move was seen as an attempt to stop his coalition partners from supporting calls for a snap poll.

Sacking threat

Mr Olmert's Kadima party has just 29 MPs out of a total of 120 seats in the parliament, the Knesset, and relies on the Labour Party's 19 MPs as key allies in its governing coalition.

With Labour supporting the motion, Mr Olmert's coalition is not likely to have enough votes to block the bill, although some smaller factions have yet to announce how they will vote.

Mr Olmert has threatened to fire Labour cabinet ministers if they back the vote but Labour's secretary general Eitan Cabel said ministers were ready to lose their jobs and head for early elections.

"If the prime minister fires the Labour ministers this may very well lead to elections," he said.

"We took that into account before the vote."

Dissolving parliament would mean moving forward a general election, which is currently scheduled for late 2010.

Fresh elections would almost certainly put paid to a US-sponsored negotiating timetable which envisioned peace with the Palestinians by the end of the year.