Singapore on Wednesday hanged a man for trafficking drugs, authorities said, in the city-state's second execution in three weeks.

The man was convicted in 2019 of trafficking around 1.5 kilos (3.3 pounds) of cannabis, Kokila Annamalai of local rights group Transformative Justice Collective told AFP.

Singapore has some of the world's toughest anti-narcotics laws: trafficking more than 500 grams of cannabis can result in the death penalty.

"A 36-year-old Singaporean man had his capital sentence carried out today at Changi Prison Complex," a spokesman for the city-state's prison service told AFP.

Singapore's Central Narcotics Bureau (CNB) said in a separate statement that it would not release the name of the man to respect his family's wish for privacy.

"The person was accorded full due process under the law, and had access to legal counsel throughout the process," CNB added.

A last-ditch appeal to review the case and stay his execution was dismissed on Tuesday, Annamalai said.

Despite growing international calls to abolish the death penalty, Singapore insists that it is an effective deterrent against trafficking.

The Wednesday execution was the second in Singapore this year after Tangaraju Suppiah, 46, was hanged on April 26 for conspiracy to smuggle a kilo of cannabis.

Thirteen death row inmates have been hanged since Singapore resumed executions in March 2022 after a hiatus of more than two years.

Tangaraju Suppiah's execution sparked an international outcry, with rights groups pointing to "many flaws" in the case, but the Singapore government said his guilt was proven beyond a reasonable doubt.

Activists said they will continue to push for Singapore to abolish capital punishment as it has no proven deterrent effect on crime.

"The call to the Singapore government (to scrap the death penalty) has been loud and clear globally, and we will repeat the call: Singapore has to halt the executions," Amnesty International's executive director for Malaysia Katrina Jorene Maliamauv told reporters in Kuala Lumpur on Tuesday. "They have to commute all existing death sentences."

Among those hanged last year was Nagaenthran K. Dharmalingam, whose execution sparked international condemnation because he was deemed to have a mental disability.

(AFP)

The gallows at Singapore’s Changi Prison Complex. (AP)

Singapore executes second prisoner in three weeks