Boxing superstar Manny Pacquiao visited a Filipina on death row in Indonesia on Friday, with the convict breaking down in tears as she prayed behind bars with the Philippine sporting hero.

Mary Jane Veloso was sentenced to death in Indonesia after being arrested in 2009 with 2.6 kilograms (5.7 pounds) of heroin sewn into the lining of her suitcase.

She had been due to face the firing squad along with other foreign drug convicts in April but was granted a temporary reprieve after a woman suspected of recruiting her was arrested in the Philippines.

Indonesian authorities have insisted the case of Veloso, who has always maintained her innocence claiming that human-traffickers duped her, has only been postponed while legal proceedings run their course in the Philippines.

"We're hoping to help save Mary Jane's life, I think Mary Jane is a victim of human-trafficking," Pacquiao said after visiting the single mother of two young children in Wirogunan prison on the main island of Java.

During a 30-minute meeting, Pacquiao and his wife Jinkee prayed with Veloso. The convict broke down in tears as she prayed, a government official who witnessed the meeting told reporters, and at one point tightly embraced the boxing star.

They swapped gifts, with Veloso giving Pacquiao a blue scarf emblazoned with his nickname "Pacman", and the boxer giving her money. However prison officials said they would keep the money for her as it was against the rules for inmates to have cash. They did not say how much it was.

Pacquiao, who was in Indonesia to film a television advert, was also hoping to raise her case with President Joko Widodo during a visit to the capital Jakarta later Friday.

Her case attracted huge attention in both Indonesia and the Philippines, with near daily rallies of support and celebrities urging Jakarta to show her mercy.

Pacquiao is an international star who last made global headlines in May when he was beaten by Floyd Mayweather in Las Vegas in what was dubbed "the fight of the century".

Widodo has vowed there will be no clemency for drug traffickers on death row as Indonesia is facing an "emergency" due to rising narcotics use.

Seven other foreign drug convicts and one Indonesian were executed as planned on the prison island of Nusakambangan in late April, sparking an international outcry.