Sri Lanka has decided to re-enforce the death penalty as part of attempts to fight drug trafficking in the country, a senior cabinet minister said on Wednesday.

President Maithripala Sirisena and the cabinet decided to enforce the death penalty for 19 people already sentenced to death, who are reportedly involved in the smuggling of narcotics while in prison, Minister Dr Rajitha Senaratne, a government spokesman, said.

"The government also has decided to deploy the army to crack down on drug traffickers," Senaratne told a news conference.

Sri Lanka currently does not enforce the death penalty, although courts do hand out death sentences for charges of murder, drug offences and rape.

The death penalty was last enforced in Sri Lanka in 1976.

Currently, 743 convicts who have been handed death sentences remain in prison, with appeals for 472 people still pending.

The move to crack down on drug offenders comes amid reports that prisoners, mostly using mobile phones, are directing drug trafficking operations while serving their jail terms.

Reacting to the news, Amnesty International called on Sri Lanka to halt any plans to implement the death penalty and "preserve its longstanding positive record on shunning this cruel and irreversible punishment."