"Over 20,000 residential and non-residential buildings with a cubic capacity of 92 million cubic metres were either completely destroyed or severely damaged," Arkadiusz Mularczyk said.

Mularczyk led a parliamentary team which prepared a report on Poland's WWII losses with a view to claiming war reparations from Germany.

Law and Justice (PiS) leader Jarosław Kaczyński announced in mid-July that the first part of the report was likely to be published on September 1.

"It has been estimated that around 10 per cent of residential and non-residential buildings in Warsaw were destroyed during the September 1939 campaign after WWII's outbreak, 15 per cent during and after the Warsaw Ghetto Warsaw Uprising in 1943, 25 per cent during the Warsaw Uprising in 1944, and another 30 per cent after the end of the uprising in October-December 1944," Mularczyk told PAP.

"A total of over 80 per cent of all buildings in Warsaw were destroyed," he said, adding that the data came from a report on Warsaw's war losses prepared by the team for Warsaw war losses upon a 2004 motion by the city's then mayor, Lech Kaczyński.

According to Mularczyk, in 2004, Warsaw WWII losses were estimated at USD 54.6 billion.

"After indexation, this would amount to USD 85 billion (PLN 381 billion or EUR 80.8 billion) on June 30, 2022," the PiS MP said, adding that Warsaw's material losses accounted for 34 per cent of Poland's total WWII losses.

Before the war, Warsaw's population amounted to 1.2 million people. It has been estimated that 685,000-700,000 Warsaw residents were killed during the war.