The German government has rejected claims by Polish officials that it should pay billions of dollars in reparations for World War II.

Key figures in Poland's right-wing government said recently that Germany has a moral obligation to pay for the massive destruction of many towns and cities by the Nazi war machine.

The demand has been voiced by a number of officials, most recently by Prime Minister Beata Szydlo, who spoke of her plans to push for a payment in an interview with Polish broadcaster RMF FM.

Responding to Szydlo's comments, German government spokesman Steffen Seibert on Friday cited a postwar declaration in which Poland had waived its right to further compensation.

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While insisting that Germany took full responsibility for the "unspeakable crimes" of Nazi Germany, Seibert said his government saw "no reason to doubt the internationally binding effect of the 1953 reparations waiver."

Poland suffered massively at the hands of invading Nazi Germany in World War II; some six million people were killed.

The renewed debate over payments by Germany to its formerly occupied neighbour comes at a time of already tense relations between Berlin and Warsaw, due to political differences over migration and an ongoing legal procedure against Poland by the European Union.

An exact figure has not been placed on the restitution that Poland intends to seek.

Interior Minister Mariusz Blaszczak placed the sum of material damages at one trillion dollars in a televised interview.

Foreign Minister Witold Waszczykowski later said in comments to RMF: "Perhaps even more."

In 2015, Germany dismissed similar demands from Greece to pay it World War Two reparations - Nazis destroyed hundreds of Greek villages and killed more than 20,000 civilians between the 1941-1944 occupation of the southern European country.

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On Friday, Poland's powerful Roman Catholic church warned that "poor decisions" by the country's right-wing leaders could "undermine" ties with Germany.

"The manner in which unresolved issues are dealt with in the relations between the two countries is of utmost importance," according to a statement signed by five of Poland's most senior clerics.

"They need to be conducted on a level of wise diplomacy to maintain hard-won trust, not to be undermined by arousing negative social emotions on either side," said the church leaders, including Cardinal Kazimierz Nycz and Archbishop Henryk Muszynski.

According to a survey by Poland's independent Ibris pollsters published last month, 51 percent of Poles oppose any reparation claims against Germany, while 24 percent believe such claims ought to be made.