Archbishop of Turin, Cardinal Severino Poletto, stands in front of the Holy Shroud on Saturday. (Luca Bruno/Associated Press)

The Shroud of Turin, believed by many Christians to be the burial cloth of Jesus Christ, went on public display Saturday for the first time in a decade at a cathedral in northern Italy.

Over the next six weeks, about two million people are expected to view the linen bearing the faded image of a bearded man.

The faded image of a bearded man appears on the shroud, a 4.3-metre-long linen revered by some as the burial cloth of Jesus. (Luca Bruno/Associated Press)

Each visitor will be allowed five minutes to stand before the bulletproof, climate-controlled case containing the cloth inside northern Italy's Turin Cathedral, where it has been kept for 500 years. In that time, the public has been allowed to view it on only five occasions. The last time was in 2000.

The shroud was discovered in the French city of Troyes in the mid-14th century. It underwent a major cleaning and restoration in 2002.

Restorers removed 30 patches sewn on by nuns in 1534, two years after the cloth was damaged in a fire.

Bruno Barberis, head of the international centre on the shroud, said no one has yet been able to explain how the image on the cloth was formed.

"We are practically sure that it is the image left by a human corpse, not a painting or an image obtained in some other human way," he said.

Carbon dating in 1988 claimed the image of the man could not be that of Jesus because the shroud was medieval. But many have rejected that result and want further scientific tests to be carried out.

Pope Benedict XVI will visit Turin on May 2 to pray before the 4.3-metre-long, one-metre-wide shroud.