A worker checks a billboard promoting the upcoming visit of Pope Francis in Ciudad Juarez, Mexico. Picture: Reuters/ Jose Luis Gonzalez

Rome - Pope Francis begins a high-profile visit to Latin America on Friday in what should be a series of celebrations for the Argentinian pontiff.

Attention instead looks set to be fixed again on arguably the single most shocking case of multiple child abuse, cover-ups and conspiracy in a series of worldwide clerical paedophilia cases.

Even before Francis touches down in Mexico city, victims of serial abuser Marcial Maciel, the close friend of Pope John Paul II, and head of the Legionaries of Christ, are dismayed that Pope Francis will not find time to meet them despite him spending a whole week in Mexico.

The Mexican religious institution had at its height 800 priests, 15 universities, and more than 100 prep schools.

Maciel, who died in the US in 2008, aged 86, is said to have exploited his power and position to abuse boys and young men for many decades.

It is even thought he abused two of his own children from relations with two women.

Despite this, he continued to have the ear of Pope John Paul II, and accompanied him during papal visits to Mexico in 1979, 1990 and 1993 - long after formal charges had been filed against him in ecclesiastical courts in Rome.

Barbara Blaine, the president of the US-based support group SNAP (Survivors Network of those Abused by Priests), said: “Of course, Francis should meet with the Mexican victims. But it seems he only meets victims of abuse for good PR.”

She added: “He doesn't seem to meet the victims who are likely to cause controversy.”

Given the “proven layers of conspiracy and cover-up” over Maciel, she said such a meeting would not be easy for the Vatican to “stage manage”.

Victims of Maciel were dismayed not to be offered a chance to see Pope Benedict when he visited Mexico in 2012.

Critics were even more upset when Pope Francis recently extended an olive branch to the shamed, ultra-conservative order, founded by Maciel in 1941. In October last year, the pontiff granted a “plenary indulgence” pardoning the current Legionaries. Critics say that 30 or so priests in the institution are thought to have been abusers.

One prominent victim, José Barba, a university professor, who was abused by Maciel in his youth, told the Mexican press ahead of the pope's visit that survivors were “still waiting for justice” and he urged the pope to meet them.

Marco Politi, a biographer of Pope Francis, told The Independent: “The victims of Maciel have the right to see the Pope given that they were let down by Benedict who refused to meet them back in 2012 when he was in Mexico.”

Vatican spokesman Father Federico Lombardi insisted there would be no meeting, but remained upbeat. “I don't think we can expect a meeting with victims of child abuse,” he said, adding: “I remember the sea of people when John Paul II visited... everyone loves the Pope.”

Persistent questions over John Paul II's continued support for Maciel caused some experts to question whether the Polish pope would get a fast-tracked sainthood.

In the event he was canonised in 2011 - just nine years after his death.

A year before, in 2010, the Vatican finally apologised for the crimes of Maciel, noting the Mexican priest had “lived a life without morals”, 40 years or more after the first documented reports of his sex attacks on children.