The family members of a Malaysian on death row in Singapore have called for the intervention of Putrajaya to halt his upcoming execution in Changi Prison on Friday.

The family of 32-year-old Pannir Selvam Pranthaman said they submitted a final clemency appeal to Singapore President Halimah Yacob today.

Pannir was not given his chance of clemency under Singapore law, said Sangkari, Pannir's sister in a statement today.

She said the family was stunned last week when it received the letter refusing clemency and a notice of execution dated the same day.

"Obviously, this can't be right. Pannir was not given his chance for clemency under the Singapore laws," she said.

"Neither did the public prosecutor give Pannir the certificate of assistance despite him having provided information to the authorities. This certificate could save his life and is his entitlement," she added.

"We now make this open and urgent appeal to the Malaysian government to take this up with the Singapore government, to appeal for Pannir's life," she said.

"The Malaysian government is Pannir and our family's last hope. We implore the Malaysian government to communicate and urge the Singapore government to halt Friday's execution.

"Please give Pannir and our family a second chance," pleaded Sangkari.

"He is a good person who came from a good home. He has always been kind and selfless to others.

"This may seem contradictory as he has been convicted. But this is the truth that we know and which keeps us alive and hoping," she added.

Last week, Lawyers for Liberty adviser N Surendran pleaded with the Malaysian government to make strong representations for the death sentence imposed on P Pannir Selvam, 32, to be commuted to imprisonment.

Pannir was convicted on June 27, 2017, of trafficking in 51.84g of diamorphine at the Woodlands Checkpoint, in September 2014.

He has denied knowing he was carrying prohibited drugs, and the Singapore High Court judge, in convicting him, had also found that he was a mere drug mule.