The eight-member panel will hear testimony for five days in the capital Colombo and two days in Vavuniya, near the former war zone, an official statement said Tuesday.
The probe is expected to focus on why a 2002 truce between the government and separatist Tamil Tiger rebels collapsed and led to more fighting.
The president's office said in a statement that the panel was also tasked with recommending measures to ensure that Sri Lanka did not return to conflict.
Sri Lanka has rejected a separate United Nations probe into alleged rights abuses during the final stages of the war.
The UN has previously reported that at least 7,000 ethnic Tamil civilians were killed in the last four months of fighting before government troops finally defeated the Tigers in May.
Sri Lanka says that no civilians were killed while battling the rebels and that it would not allow the UN or any other independent body to probe war crimes allegations.