Sirisena ordered Presidential Pardon for former LTTE cadre Sivaraja Jenivan, currently undergoing a 10-year rigourous imprisonment sentence, for trying to murder him in 2005 when he was serving as the country's Minister of Mahaweli Development.
Jenivan was arrested in 2006 inside a passenger bus leaving Sirisena's hometown Polonnaruwa.
He was sentenced to 10 years rigorous imprisonment by Polonnaruwa High Court last year, the Colombo Page reported.
The pardon for 36-year-old Jenivan came on the day when Sirisena finished his first year in office after defeating Lanka's former strongman Mahinda Rajapaksa last year.
Earlier this week, the president promised to give land to civilians displaced by war in the embattled northern and eastern provinces, by the middle of this year.
Sirisena, 64, had came to power in January last year with the backing of country's minority Tamils and Muslims in addition to the majority Sinhalese on the back of promises to ensure ethnic reconciliation and end the corruption.