The Singapore government criticised British billionaire Richard Branson on Tuesday for saying authorities "may be about to kill an innocent man" over one kilogram of cannabis.
Singaporean Tangaraju Suppiah, 46, is scheduled to be hanged on Wednesday after being convicted of conspiracy to traffic 1,017.9g of cannabis, twice the minimum amount that merits the death sentence under the city-state's tough drug laws.
Branson, a member of the Geneva-based Global Commission on Drug Policy, urged Singapore on his blog on Monday to halt the execution, saying Tangaraju was "not anywhere near" the drugs at the time of his arrest.
He warned that Singapore might be about to put an innocent man to death.
"This is patently untrue," Singapore's home affairs ministry said in a statement, adding that Tangaraju's guilt had been proven beyond reasonable doubt.
Branson showed "disrespect for Singapore’s judges and our criminal justice system with such allegations", it said.
It will be Singapore's first execution in six months and the 12th since last year.
Cannabis has been decriminalised in many parts of the world, including in neighbouring Thailand. Rights groups have been appealing to Singapore to abolish capital punishment.
The Asian financial hub has some of the world's toughest anti-narcotics laws and insists the death penalty remains an effective deterrent against trafficking.
Tangaraju’s family pleaded for clemency on Sunday and urged a retrial.
Singapore resumed executions in March 2022 after a hiatus of more than two years.
Among those hanged was Nagaenthran K Dharmalingam, whose execution sparked a global outcry, including from the United Nations and Branson, because he was deemed to have a mental disability.
Singapore invited Branson to a televised debate on the death penalty last year but the billionaire businessman declined, saying authorities should instead engage with local rights activists.