PRETORIA (AFP) - A terminally-ill South African man died of natural causes on Thursday on the same day that a court granted him the right to end his life, a ruling that could pave the way for assisted suicide legislation.

Retired advocate Robin Stransham-Ford, 65, was reported to be heavily sedated and a statement from his family did not say whether he died before or after the ruling.

"Since receiving the heartening news of the ground-breaking judgement, we are deeply saddened to announce that Robin has passed away," the family said.

"It was in the presence of his family and carers that Robin died peacefully."

Dignity SA, which lobbies for assisted suicide legislation, said that Stransham-Ford "died peacefully of natural causes".

The High Court in Pretoria on Thursday ruled that Stransham-Ford, who suffered from prostate cancer, could have a doctor help him end his life, and that the doctor would be protected from prosecution.

Medically-assisted suicide remains illegal in South Africa, but there have been growing calls for it to be legalised.

Judge Hans Fabricius said in his ruling that Stransham-Ford was entitled "to end his life, either by administration of a lethal agent or by providing the applicant with the necessary lethal agent to administer himself."

Dignity SA said it expected the judge's decision to "set in motion the process of legalising assisted dying in South Africa."

Assisted suicide is illegal in many parts of the world.

Switzerland is one of the few countries in Europe that allows doctors help patients end their lives.

In February, Canada's supreme court lifted a ban on doctor-assisted suicide for mentally competent adults suffering from an incurable disease.

A South African professor, Sean Davison, was in 2010 found guilty by a New Zealand court of helping his cancer-stricken mother take her own life by giving her a lethal dose of morphine.

The suicide occurred in New Zealand, where Davison was living. He was placed under house arrest for five months.