A long-awaited final report into Israel's conduct of the 2006 war in Lebanon is due to be published.
The PM is the only figure criticised in the interim report to keep his job
Hostilities broke out in July 2006, when the Lebanese Islamist Hezbollah group captured two Israeli soldiers.
In the month-long conflict that followed, more than 1,000 Lebanese died, mostly civilians, along with 160 Israelis, mostly soldiers.
An interim report last April was highly critical of PM Ehud Olmert, his government and top military leaders.
There were calls for Mr Olmert to resign, but he has said he will never step down.
Opinion polls suggest most Israelis want Mr Olmert to step down if the commission's criticism is "very severe", while only a quarter say he should stay on whatever the findings.
The 62-year-old is buoyed by support from Israel's superpower ally, the US, to try to make peace with the Palestinians this year, though negotiations have faltered from the start.
The government-appointed commission, headed by retired judge Eliyahu Winograd, will give Mr Olmert a copy of the report at 1700 (1500 GMT).
An unclassified version will be released to the public after a news conference about an hour later.
Defence Minister Ehud Barak, whose Labour Party is in coalition with the governing Kadima party, said last summer that he would resign from the government when the Winograd report was published.
However, he has appeared subsequently to back down, saying he would read the final report and "do what was best for Israel".
In its interim findings, the commission accused Mr Olmert of lacking "judgment, responsibility and prudence" in his decision to go to war.
The final report is expected to focus on the last hours of hostilities, when Mr Olmert ordered a ground offensive in which 33 soldiers died as a UN-brokered truce was being finalised.
Mr Olmert says he has already acted to implement the panel's early recommendations.
But public disappointment in Israel with the performance of the country's army and government resulted in the resignation of the then-Defence Minister and Chief of Staff.