Gunawardena embarked on active politics in late 1970s, entered Parliament in 1983, and then held cabinet ministerial portfolios under several governments, Ada Derana web portal reported.
He was also Chairman of three Parliamentary Committees to determine the electoral reforms, was the leader of the House and the head of Government in the Sri Lankan Legislature.
Born in 1949 and son of the leftist politician Philip Gunawardena, Dinesh Gunawardena has led the left-wing Mahajana Eksath Peramuna party since 1983.
This week, President Ranil Wickremesinghe was sworn in at the Parliament complex as the 8th Executive President of Sri Lanka before Chief Justice Jayantha Jayasuriya and in the presence of head of Parliament, Mahinda Yapa Abeywardena.
Sri Lanka is going through the worst economic crisis since its independence from the British colonialism in 1948, aggravated by soaring prices of raw materials and commodities, as well as long power cuts.