Former hardline Iranian president Mahmoud Ahmadinejad said Tuesday he will not compete in next year's presidential vote, following advice from Iran's supreme leader, media reported.

"In following the will of the great leader of the revolution, I have no plans to be present in next year's presidential competitions," he wrote in a letter to Ayatollah Ali Khamenei published by Iranian media.

It came a day after Khamenei, in his own cautiously worded remarks, said: "A certain person came to me and I told him not to do a certain thing, believing it would be to the benefit of both the person himself and the country."

Khamenei implied that Ahmadinejad's candidacy would create "a bi-polar atmosphere" that would "damage the country".

The hardline former president had made numerous public appearances in recent months, leading to speculation that he was planning a comeback in elections next May.

The news is likely to reassure moderate President Hassan Rouhani, who is expected to run for a second term on May 19.

Ahmadinejad's inflammatory rhetoric -- particularly regarding Iran's nuclear programme and hostility towards Israel -- was blamed for deepening tensions with the West, but his populist approach and humble roots means he has retained popularity with poorer sections of Iranian society.

Rouhani, who oversaw a deal with world powers to end sanctions in exchange for curbing Iran's nuclear programme, faces mounting pressure from conservatives who say the accord has brought few benefits to Iran.