Nuclear power should be considered a useful energy source, a senior Catholic cardinal has said on Wednesday.

The cardinal also went as far as criticising countries such as Italy which have banned the technology on principal.

Weighing into a debate that sharply divides environmentalists, many of whom see nuclear as unsustainable and unsafe, Cardinal Renato Martino said nuclear power could be part of a balanced energy mix, alongside "forms of clean energy".

"With maximum safety requirements in place for people and the environment, and with a ban in place on the hostile use of nuclear technology, why should the peaceful use of nuclear technology be barred?" Martino, the Pope's justice minister, told Vatican Radio.

While Iran's nuclear programme has highlighted concerns about proliferation of nuclear weapons, many countries in Europe have chosen not to have nuclear power plants due to concerns about the environment and potential accidents. Martino said such a policy might be counterproductive.

"Excluding nuclear energy because of a preconceived principle or for fears of disasters could be a mistake and in come cases could have paradoxical effects.

"One should think of Italy, which abandoned the production of nuclear energy in 1987 but which imports the same type of energy from France," said Martino, a former papal envoy to the United Nations.

Italians voted in a referendum to ditch nuclear power in the wake of the 1986 Chernobyl disaster. Supporters of nuclear power say it could be used as a way of reducing reliance on fossil fuels which emit greenhouse gases blamed for global warming.

Pope Benedict on Sunday marked the fiftieth anniversary of the International Atomic Energy Agency by calling for "progressive and agreed nuclear disarmament and to favour the peaceful and assured use of nuclear technology for real development".