Pope Francis has warned against the resurgence of nationalism around the world, saying that politics should not be limited to seeking short-term solutions.

In a New Year's speech to the diplomatic corps on Monday - known informally as his "state of the world" address, the Pope said the resurgence of nationalist impulses being seen in the world today was damaging the modern global multilateral system which had first emerged in the wake of World War I.

"The reappearance of these impulses today is progressively weakening the multilateral system, resulting in a general lack of trust, a crisis of credibility in international political life, and a gradual marginalisation of the most vulnerable members of the family of nations," he said, according to a transcript of the speech published by Vatican News.

The Pope said it was troubling to see the re-emergence of tendencies "to impose and pursue individual national interests without having recourse to the instruments provided by international law for resolving controversies and ensuring that justice is respected, also through international courts".

"Such an attitude is at times the result of a reaction on the part of government leaders to growing unease among the citizens of not a few countries, who perceive the procedures and rules governing the international community as slow, abstract and ultimately far removed from their own real needs," he said.

While noting that it was fitting political leaders "listen to the voices of their constituencies and seek concrete solutions to promote their greater good", he added: "Yet this demands respect for law and justice both within their national communities and within the international community, since reactive, emotional and hasty solutions may well be able to garner short-term consensus, but they will certainly not help the solution of deeper problems; indeed, they will aggravate them...Politics must be farsighted and not limited to seeking short-term solutions."

Francis also emphasised the commitment of the church and its agencies to aiding those in need - "to give a voice to those who have none" and, mentioning specific crises around the world, he appealed for the international community to find a political solution to the ongoing conflict in Syria as well as for governments to assist "all those forced to emigrate on account of the scourge of poverty and various forms of violence and persecution, as well as natural catastrophes and climatic disturbances".

He also described the abuse of children, including by some members of the clergy, as "one of the plagues of our time", describing it as "one of the vilest and most heinous crimes conceivable".