Mr Kitsmarishvili is seen as an outspoken critic of Mr Saakashvili
A former Georgian ambassador has caused uproar in Georgia by saying his country, not Russia, started August's war over South Ossetia.
Erosi Kitsmarishvili, a former envoy to Russia, was testifying at a parliamentary commission hearing into the war the breakaway Georgian region.
One lawmaker threw his pen at Mr Kitsmarishvili and then had to be restrained as he charged towards him.
Georgia maintains its assault on South Ossetia followed a Russian invasion.
"Russia was ready for this war, but the Georgian leadership started the military action first," Mr Kitsmarishvili told the commission on Tuesday.
He said he had this information "from high-ranking Georgian officials". However, he said he believed Georgia had been provoked into war by Russia.
Mr Kitsmarishvili has been an outspoken critic of the Georgian president since being replaced as ambassador to Moscow, the BBC's Tom Esslemont in Tbilisi says.
On Tuesday, the former envoy also claimed that Mr Saakashvili told him in March of plans to use force to retake Abkhazia - another Georgia's rebel region.
He said the president had also told him he would move the Georgian capital to Abkhazia's capital, Sukhumi, in August.
Several members of the bi-partisan commission and Georgian government officials described Mr Kitsmarishvili's comments as "shameless" and "irresponsible".
Georgia accuses Russia of sending troops and tanks into South Ossetia in the hours before Tbilisi launched its assault on the regional capital Tskhinvali on 7 August.
Moscow says it intervened only after Tbilisi began shelling the rebel region.
Russian forces ousted Georgian troops from South Ossetia during the five-day war.
Moscow still keeps thousands of its troops in South Ossetia and Abkhazia.