JAKARTA (AFP) - Indonesian President Joko Widodo has defended his decision to reject clemency for foreigners on death row for drug smuggling, but said he does not rule out abolishing capital punishment in the future.

Indonesian authorities this week moved the two Australian ringleaders of the so-called "Bali Nine" drug trafficking gang from Bali to the prison island of Nusakambangan, indicating they would soon be executed.

They are among a group of drug convicts, including foreigners from France, Brazil, the Philippines, Nigeria and Ghana, who are expected to be executed at the same time on the island.

In an interview to Al Jazeera, Widodo defended his decision to not halt the planned executions, which have sparked diplomatic tensions with Canberra.

"About 4.5 million people need to be rehabilitated because of the drugs. Please do not only see the traffickers but also the impact of the drugs trafficking," he said.

"Please do visit the (drugs) rehabilitation centre when they are screaming due to the drugs addiction. People must see this from both side, not only from one side," he added.

But Widodo said that the government would be open to abolishing the death penalty if the Indonesian people wanted change.

"The Constitution and existing laws still allow (the death penalty) but in the future if it is necessary to change it and the people really want it, why not?" he said in the interview broadcast on Saturday.

"I think we want to listen to what people want first. It's still a long time to go through and I do not want to talk about the issue now," he added.

Canberra has warned Jakarta that the execution of the two Australians would have implications, not just in Australia but globally.

UN human rights spokesman Rupert Colville called on the Indonesian government to halt the executions on Friday, urging the authorities to "reinstate its moratorium on the death penalty and conduct a thorough review of all requests for pardon".