Six non-European Catholic prelates will join the Vatican's College of Cardinals in a move which may influence the election of the future pope, amid uncertainty over Pope Benedict XVI's health.

The 85-year-old Benedict, who has been looking increasingly tired and worn, said Wednesday he will appoint cardinals from Colombia, India, Lebanon, Nigeria, the Philippines and the United States in a surprise consistory in November.

The college, the elite body that advises the pontiff and elects his successor upon his death, is currently heavily weighted in favour of Europe.

Religious watchers had not expected there to be another consistory until next year and the surprise announcement sparked concern among Vatican watchers that the elderly pontiff's health may be worse than thought.

Religious observers note that the pope appears to have been particularly hard hit by the child abuse scandals rocking the Church and the betrayal of his personal butler, who was found guilty this month of stealing private memos.

As Cardinal Joseph Ratzinger, he suffered a stroke while vacationing in the Alps which briefly affected his eyesight and weakened his heart. The Vatican said he suffered another mild stroke in May 2005 after being elected pope.

The consistory, which is set to take place on November 24, follows the death of several cardinals in recent months and will bring the number of those eligible to vote back up to the maximum of 120.

Cardinals must be under 80 years old to take part in a papal election.

The new cardinals will be the American James Michael Harvey, Lebanon's Bechara Boutros Rahi, India's Baselios Cleemis, Nigeria's John Onaiyekan, Colombia's Ruben Salazar Gomez and Filipino Luis Antonio Tagle.

In February, 22 new "princes of the Church" were created amid criticism of the number of Europeans and poor representation from elsewhere.

While nearly half of the world's Catholics are in Latin America, there was only one new cardinal appointed from "the Catholic continent".

The nomination of seven Italians in Benedict's fourth consistory also brought to 30 the elector cardinals from Italy -- almost a quarter of the total, far outweighing any other country.

The nominations sparked rumours of a power struggle at the heart of the Vatican, with some observers saying that Secretary of State Tarcisio Bertone was behind the promotion of Italians up the Roman Catholic Church hierarchy.

After the new consistory, there will be 62 European cardinals eligible to vote (compared to 67 in February), 14 North Americans, 21 South Americans, 11 Africans and 11 Asians.