Singapore has executed a man for conspiring to traffic cannabis despite pleas for clemency from his family, activists and the United Nations.

Tangaraju Suppiah, 46, was hanged at dawn on Wednesday over a plot to smuggle 1kg (35oz) of cannabis.

Activists said he had been convicted on weak evidence and received limited legal access during his prosecution.

But Singapore authorities said he had been given a fair trial and criticised those who questioned the courts.

Singapore has some of the world's toughest anti-drug laws. It argues these are a necessary deterrent to drug crime which is a major issue elsewhere across South-East Asia.

On Wednesday, Tangaraju Suppiah's family gathered at Changi Prison near the city's airport in the east to receive his body.

"The family said they weren't going to give up on him until right until to the end," anti-death penalty activist Kirsten Han told the BBC.

"They still have a lot of unresolved questions about his case, and the evidence against him. It has been such a harrowing experience for them."

Last year Singapore hanged 11 people, all on drugs charges - including an intellectually impaired man convicted of trafficking three tablespoons of heroin.

The nation's stringent drug laws and use of capital punishment put it increasingly at odds with advanced nations and others in the region, activists say.

Singapore's neighbour Malaysia abolished mandatory death penalties earlier this month, saying it was not an effective deterrent to crime.

Meanwhile cannabis has been decriminalised in many parts of the world - including in neighbouring Thailand, where its trade is encouraged.

Singapore's courts on Tuesday had rejected a last-minute appeal from Tangaraju Suppiah's family against his conviction.

Supporters had also petitioned Singapore's President Halimah Yacob for a reprieve, while British activist billionaire Sir Richard Branson added his voice to those calling for a case review.

The UN's Human Rights Office had on Tuesday also called on Singapore to "urgently reconsider" the execution, saying the death penalty violated international norms.

Tangaraju Suppiah had been convicted of "abetting by engaging in a conspiracy to traffic" about 1kg (35oz) of cannabis from Malaysia to Singapore in 2013.

He was not found with the drugs or during the delivery. But prosecutors said he had been responsible for co-ordinating it, and they traced two phone numbers used by a deliveryman back to him.

Tangaraju denied his involvement - and said he had not been the person communicating with the deliveryman. He said he had lost one of the phones and denied owning the second one.

Singapore's law mandates the death penalty for those guilty of trafficking narcotics - including cannabis, cocaine, heroin, and ketamine - beyond a certain quantity.

Convicted traffickers who can prove that they were only couriers may be able to avoid the death penalty. Drug possession and consumption draw lesser punishments including prison and fines.

In Tangaraju Suppiah's last appeal, the judge agreed with the prosecution that he had been responsible for co-ordinating the delivery, which made him ineligible for a more lenient sentence.

Activists had raised concerns that he had not been given adequate access to a Tamil interpreter and had been forced to represent himself at his last appeal because his family was unable to secure a lawyer.

Singapore authorities say he requested an interpreter only during the trial, and not earlier. They also said he had access to legal counsel throughout the process.

Sir Richard, who had previously criticised the 2022 execution of intellectually impaired Nagaenthran Dharmalingam, said the latest case was "shocking on multiple levels".

In a blog post on Monday, he said Singapore "may be about to kill an innocent man" on the back of "more than dubious circumstances".

Rebutting his allegations, Singapore's Home Affairs Ministry accused him of "disrespect for Singapore's judges and our criminal justice system".

It said the death penalty was "an essential component" in a multi-pronged approach that had been "effective in keeping Singapore safe and secure".

Tangaraju Suppiah's case marked the country's first execution this year.

Singapore is one of 35 countries and territories in the world that sentence people to death for drug crimes, according to Harm Reduction International (HRI), a non-profit, non-government organisation.

It is also considered a "high application" country, where at least 10 executions have been carried out in the past five years.

The US and South Korea are the only two OECD member countries that have retained the death penalty for drug offences, but they have not carried out such executions in the last five years, according to HRI.