Families of death row convicts urged the Singapore government Monday to impose a moratorium on capital punishment to allow for an independent review of the controversial use of executions in the city-state.

Five families called for a meeting with Singapore's law and home affairs minister "to listen to our stories, to our pain, and confront our humanity", they said in a statement on the eve of World Day Against the Death Penalty.

At least 16 people convicted on drug trafficking charges have been hanged since Singapore resumed executions last year after a two-year pause during the Covid-19 pandemic.

"We seek an immediate moratorium of the death penalty, and a transparent and independent review of the use of capital punishment," the families said.

The United Nations, rights groups and other opponents of capital punishment say it has no proven deterrent effect and have called for it to be discontinued.

Singaporean officials insist it has helped make the country one of Asia's safest.

"We stand here on behalf of many more families… whose lives have been devastated by Singapore's ruthless and senseless war on drugs," the families said.

They have also submitted a similar petition to the government.

Activist Kokila Annamalai of the Transformative Justice Collective said a moratorium would be an "easier first step" towards eventual abolition as it is easier to implement and is less controversial.

"It still keeps the death penalty on the books and allows the public time to debate and develop a deeper understanding of the death penalty," she said.

As of July 5, at least 63 convicts were sitting on death row in Singapore, according to the petition.

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

Also hanged for drug trafficking was Saridewi Binte Djamani, 45, the first woman to be executed in the city-state in nearly 20 years.

Singapore has some of the world's toughest anti-drug laws. Trafficking more than 500 grams of cannabis or over 15 grams of heroin can result in the death penalty.