A key parliamentary committee in Israel has called for a powerful state inquiry into official failures during the recent Lebanon war.
The vote is non-binding, but puts extra pressure on Mr Olmert
In a non-binding vote, the Defence and Foreign Affairs Committee passed a motion calling for it to be set up under a Supreme Court judge.
Embattled Israeli PM Ehud Olmert has argued such a probe would cause political and military paralysis.
Last week, he ordered three internal inquiries with limited powers.
Two of these will not publish their findings.
MPs supporting the state commission came from opposition groups and the Labour Party, which is in the ruling coalition.
After reports of the eight-to-three vote, the prime minister's office announced Wednesday's cabinet meeting was cancelled. Ministers had been scheduled to vote on the government's inquiry plans.
Correspondents say Mr Olmert is already reeling from criticism over the Lebanon war and is now scrambling to keep his coalition intact.
Five weeks of bitter fighting in Lebanon with Hezbollah guerrillas ended in August after a ceasefire backed by the UN.
Israel lost 116 soldiers in the fighting and failed to achieve its stated war aims of driving Hezbollah fighters from the border, stopping rocket attacks and freeing two of its soldiers captured by Hezbollah.