A week before his beatification in Rome, a growing lobby of churchmen and religious experts is challenging the speed with which the Vatican is propelling Pope John Paul II towards sainthood, just six years after his death.

Hailed as the Pope who helped to bring down communism and prayed alongside Jews and Muslims, John Paul will be beatified in St Peter's Square next Sunday night, a first step towards sainthood.

The Vatican is erecting tent cities and stocking up with millions of bottles of water for more than 300,000 people expected in Rome.

But as the crowds begin to arrive, doubts are being expressed over the decision to begin beatification proceedings immediately after John Paul's death in 2005, instead of waiting the usual five years.

Some experts question whether he is fit for sainthood at all, pointing to his poor record in handling the sex abuse allegations against priests that came to the fore during his 26-year papacy.

"I oppose this beatification and predict history will look unkindly on John Paul, who was in denial as the worst crisis since the Reformation happened in the Church," said Father Richard McBrien, a theology professor at Notre Dame University in the United States.

"My doubts are about John Paul being beatified by his successor, Pope Benedict," said the Catholic historian Michael Walsh. "It appears incestuous and akin to the habit of deifying one's ancestors."

Even as Benedict faced the fallout from accusations that scores of priests abused children around the world, he has pulled out the stops to beatify John Paul. Sorting through hundreds of miraculous cures attributed to the Pontiff, Vatican officials have selected the overnight recovery from Parkinson's disease of a French nun as the miracle required for beatification. Experts believe canonisation could follow in two to three years.

"Years from now people may be saying, why the rush?" said Father James Martin, a Jesuit priest.

Tom Reese, a theologian, added: "What we need are fewer popes and priests beatified, and more real lives."

The ramifications of the sex abuse scandal will continue as an internal Vatican report on predator priests in Ireland reportedly lands on Benedict's desk, before the publication next month of an Irish government report on the scandal. The report is expected to shed light on whether the abuse was ignored by Bishop John Magee of Cloyne, a former private secretary to John Paul.

John Paul's unwavering support for Marcial Maciel Degollado, the Mexican priest and morphine addict who ran the powerful Legion of Christ movement, has also sparked concerns. Maciel has been accused of abusing seminarians, fathering up to six children and allegedly pacifying the Vatican through large donations.

Supporters of the Pope have argued that John Paul was wary of sex abuse accusations after seeing communist officials use fake charges to discredit priests in his native Poland.

After his beatification, John Paul's remains will be moved to an ornate chapel near the entrance to St Peter's Basilica. The tomb of a 17th-century Pope, Innocent XI, will be moved to make space.