But Maithripala Sirisena suffered a new blow when 16 of his MPs joined the opposition.
Sirisena told parliament that the coalition partners should commit to a reform agenda to revive the island nation emerging from a decades-long ethnic war that claimed more than 100,000 lives.
“This is not a time for parties to engage in a power struggle,” Sirisena said after opening a new session of parliament.
“Although we formed a coalition government in August 2015, we still have not politically matured to accept and work within this reality. Consensus government is still a foreign concept to us.”
He urged the government dominated by Prime Minister Ranil Wickremesinghe’s United National Party (UNP) to work towards ethnic reconciliation to rebuild the country.
Tamil rebels who fought for independence for the island’s ethnic minority were crushed in a military offensive that ended in May 2009.
The military drive has sparked allegations that more than 40,000 Tamil civilians were killed by government forces in the final months of the war.
Sirisena said the government must address the causes of the ethnic conflict and ensure a permanent political solution so that the nation of 21 million people does not return to war.
His remarks came a day after he announced he will not retire at the end of his term in January 2020 despite a previous pledge. That pits him against Wickremesinghe who also wants to contest the presidency.
Sirisena told a public rally in the former war zone of Batticaloa on Monday that he had unfinished business and no longer intends to retire when his five-year term finishes.
Relations between Sirisena’s Sri Lanka Freedom Party (SLFP) and Wickremesinghe’s UNP have soured in recent months.
They blame each other for a humiliating defeat in February’s local council elections. Their row deepened when the UNP, senior partner in the coalition, accused Sirisena of supporting last month’s failed bid to impeach the prime minister.
There was no immediate UNP response to Sirisena’s latest announcements.
However, as the president entered the parliament building on Tuesday, 16 of his SLFP MPs formally defected to join opposition ranks as SLFP rebels.
The SLFP was previously split between Sirisena and former president Mahinda Rajapakse who still has wide support in the country and commands a majority of SLFP MPs.