Since 1976, all death sentences handed down in Sri Lanka have been commuted to life in prison.
However, Mr Sirisena decided to reinstate the death penalty after being inspired by the war on drugs waged by the Philippines' President Rodrigo Duterte.
"The war against crime and drugs carried out by you is an example to the whole world — and personally to me," Mr Sirisena told Mr Duterte during a state visit in January, according to Philippine news site Rappler.
"Drug menace is rampant in my country and I feel that we should follow your footsteps to control this hazard."
At least 5000 individuals have been murdered due to Mr Duterte's bloody and ruthless crusade against drugs so far.
According to the ABC, Mr Sirisena is preparing to reintroduce hangings within the next two months with interviews for the controversial job taking place next month.
Prison service spokesman Thushara Upuldeniya told Reuters that 436 people were now on death row, and that at least at least 25 drug offenders could be executed.
"We never know if the Government will resume the death penalty, but we want to hire two hangmen to fill vacancies and be ready if the Government wants to execute drug traffickers," he said.
Sri Lanka's last hangman quit abruptly in 2014 without taking a life after experiencing "stress" after seeing the gallows. A replacement was hired in 2018, but he reportedly never showed up.
While the Sri Lankan President argued the policy could help curb drug crime, many have slammed the decision.
Biraj Patnaik, the South Asia director of human rights organisation Amnesty International, wrote on Twitter that: "This is one job advert that should never have been put out. The government of Sri Lanka advertising for an executioner. There is no place for the death penalty in a civilised society."
However, others like Ceylon Tamil supported the move, posting: "Those who intend to damage future civilised society with greed for money should be punished."
