The Roman Catholic Church has the inalienable right and duty to convert any person to Christianity, Pope Benedict XVI said Saturday.

Evangelism is a central mission of the Church, the pope told a Vatican body that encourages Catholic missionary activity.

The appeal for the conversion of "all nations," attributed to Jesus Christ in the Gospels, remains "an obligatory mandate for the entire Church and for every believer in Christ," the pontiff said.

"This apostolic commitment is both a duty and an inalienable right, the very expression of religious freedom with its moral, social and political dimensions," he said.

Like his predecessors, Pope Benedict is keen to promote missionary zeal among Catholics, most of whom live in a world of religious pluralism and other proselytising faiths such as Islam.

The pope's message was also addressed to the faithful in countries where religious activity is strictly controlled by the state or even relegated to the private realm.

In December, the Vatican published a doctrinal note reaffirming the mission of all the faithful to seek to convert non-Catholics including members of other Christian denominations, while avoiding placing undue pressure on them.

The note highlighted the need for respect and a spirit of cooperation in dialogue with other Christians, and rejected past accusations of proselytising that have been levelled against it by the Russian Orthodox Church.

Relations between the Orthodox Church and the Holy See have been thorny, with the Moscow Patriarchate accusing the Vatican of proselytising in traditionally Orthodox lands following the breakup of the Soviet Union.

Tensions were further aggravated in 2002, after the Vatican established four permanent dioceses in Russia.