He is the former Sri Lankan High Commissioner to South Africa, Mozambique, Namibia,  Zambia, Zimbabwe, Lesotho, Angola, Botswana, and Eswatin.

[2][3][4] Sirisena Amarasekara was born in 1946 in Mideniya, which is situated in the Hambantota District, on the southern coast of Sri Lanka.

Amarasekara joined the Ministry of Planning and Economic Affairs in 1970 and served for more than 50 years in the public sector in various senior positions.

After his retirement from the public service in 2015 he served as the chairman of the 'Pavura association of Intellectual Professionals' and as the president of 'Voice for Justice' a NGO to voice against political victimization.

In September 2020, he was appointed Sri Lankan High Commissioner Extraordinary and Plenipotentiary for South Africa, Mozambique, Namibia,  Zambia, Zimbabwe, Lesotho, Angola, Botswana, and Eswatini (the Sri Lankan diplomatic missions for the aforementioned nations fall under the purview of the Sri Lankan diplomatic mission in Pretoria[5]).