VATICAN CITY -- Pope John Paul urged magistrates and lawyers on Monday to avoid working on divorce cases, which he described as "spreading like the plague", prompting accusations of intervention in state affairs.

The pope, spiritual leader of about one billion Catholics around the world, sent his warning to the legal profession during an annual meeting with Vatican magistrates.

"Marriage is indissoluble...it doesn't make any sense to talk about the 'imposition' of human law, because it should reflect and protect natural and divine law," the pope said.

"(Divorce)...has devastating consequences that spread in society like the plague."

As a result, judges and lawyers should refuse to use their professional skills with the goal of ending marriages, he said.

"Lawyers, who work freely, should always decline to use their professions for an end that is contrary to justice, like divorce," the 81-year-old pontiff said.

But the pope's message was not greeted with open arms. Lawyers and politicians said the comments were at best inappropriate and at worst interventionist.

"The laws of the state do not interfere in the laws of the church, so it would be right if the church did not interfere in the realm of judges and lawyers," Reuters quoted marriage lawyer Cesare Rimini as telling Italy's ANSA news agency.

----- Divorce: Plague or Salvation? ----

The pope was a little less demanding of magistrates, who may find it difficult to avoid being assigned marriage cases, saying they must strive to prevent divorce.

"Those working in civil law cases should avoid being personally involved in what could be understood as cooperating in divorce...they should look for effective measures to favor marriage, above all mediating conciliation," he said.

The Catholic Church is vehemently opposed to divorce and homosexual unions which it says threaten the "natural institution" of the family.

Still, politicians from both left and right-wing parties warned the church to stay out of state affairs.

"We find ourselves faced with interference in the very principles of a lay state," said Livia Turco, a former social minister in a centre-left administration.

Right-wing lawmaker Alessandra Mussolini, granddaughter of Fascist dictator Benito Mussolini, said the idea of saving marriage at all costs was "hypocrisy".

"Divorce, at times, is a salvation because it interrupts a spiral of hate and terror even for children."