"I have already signed death penalty for four (convicts). It will be implemented soon and we have already decided the date as well," Sirisena was quoted as saying by Efe news, adding that all four were drug related convicts.
Sirisena has repeatedly said that he will go ahead with executions of people convicted of crimes related to drugs as part of a hardening stance in the drive against drug-trafficking on the island.
In the beginning of the year, authorities began the extensive process of recruiting an executioner, a position that had been lying vacant for many years.
Although more than 100 candidates applied for the position, authorities are yet to appoint anyone for the post.
The Commissioner of Prisons TMJW Thennakoon said he had not been informed of the decision to carry out the executions.
If the executions carried out, Sri lanka would be ending a 42-year-long suspension of the death penalty, even though it voted in favour of a moratorium on it during the 73rd United Nations General Assembly in December 2018.
Activist and Secretary General of non-profit Amnesty International (AI) Kumi Naidoo on Wednesday urged Sirisena in a public video message to halt his plans to resume the death penalty and the execution of the four convicts.
"I reach out to you to plead for the lives of people who may soon be executed in Sri Lanka if you revive the death penalty," the South African activist said, emphasizing that the last death sentence was carried out in Sri Lanka when the current President was just 24 years old.
In a statement on Tuesday, AI also expressed concerns over the lack of transparency around the decision as the details and date have been withheld.
The death penalty remains in force in Sri Lanka for crimes including treason, murder and drug-trafficking, although the last case that received the presidential approval necessary for its application was in 1976.
( With inputs from IANS )