The Sri Lankan president, Maithripala Sirisena told the SLFP's Central Committee that the party's alignment with the UNP was the cause of its election failings at the local government elections.
All parties had been affected by internal divisions and factions, he was quoted by the Daily Mirror as saying.
"Nobody can single out a party unaffected by internal squabbles," he added.
Tensions between the ruling coalition partners have increased since the polls delivered a win to the former president, Mahinda Rajapaksa.