Prime Minister Mateusz Morawiecki said the law 'was and remains the battle for the truth during World War II and in the post-war period.' Photo: Reuters

The measure adopted in the Sejm, Poland's lower house of parliament, will remove the three-year sentence to allusions of crimes committed in Nazi concentration camps on Polish soil as "Polish", but will maintain fines for those found guilty of breaching the law.

Prime Minister Mateusz Morawiecki said the law "was and remains the battle for the truth during World War II and in the post-war period."

Michal Dworczyk, the head of Morawiecki's office, told Polish radio earlier Wednesday that the jail sentence aspect of the law had acted as a distraction to its real intention, which was "to defend the good name of Poland and the historical truth".

Morawiecki and Polish President Andrzej Duda defended the bill earlier in February, insisting that the law was aimed at protecting Poland's reputation.

Critics deplored the law as potentially stifling what they see as justified criticism of Poland's involvement in the killing of more than a million people - the majority of whom were Jewish - at the Auschwitz-Birkenau concentration camp in Nazi-occupied Polish territory.

The US-based Simon Wiesenthal Centre, a leading Jewish human rights organisation, welcomed the move with Director Efraim Zuroff stating that "there's no question that a law like this, in its original form posed a very serious threat to serious historical research on the role of Poles during the Holocaust."

The World Jewish Congress also expressed support for the initiative, saying it was pleased the Polish government had recognised the "untenable nature of its new Holocaust law".

"[As it stood before, the law] stifled any real discussion of the extent to which local Poles were complicit in the annihilation of their Jewish neighbours during the German occupation," said President Ronald S Lauder.

The Yad Vashem Holocaust Memorial in Jerusalem welcomed the vote on Wednesday, saying that it believes "the correct way to combat historical misrepresentations is by reinforcing open, free research and educational activities."

In a veiled criticism of the legislation, Yad Vashem said it supports "ensuring that educators and researchers are not hindered in grappling with the complex truth of Polish-Jewish relations before, during and after the Holocaust."