Poland said on Wednesday it would water down a divisive Holocaust law that angered the United States and Israel, and remove parts that imposed jail terms on anyone who suggested the nation was complicit in Nazi crimes.

Prime Minister Mateusz Morawiecki asked parliament to amend the law on Wednesday morning - an unexpected announcement that came as his ruling Law and Justice party (PiS) seeks to bolster security ties with Washington and faces heightened scrutiny from the EU.

Lawmakers started a debate on the changes and the lower house speaker said they will be dealt with in an "urgent procedure".

The law as went into effect in March imposed jail sentences of up to three years for anyone who used the phrase "Polish death camps" or suggested "publicly and against the facts" that the Polish nation or state was complicit in Nazi Germany's crimes.

The nationalist, right-wing government said at the time it was needed to protect Poland's reputation. Israel and its ally the United States said it amounted to a historical whitewash.

"We resign from the criminal provisions," the head of prime minister's office, Michal Dworczyk, told public radio on Wednesday morning, saying those parts of the bill would divert attention from the original point of the legislation.

The PiS government said that following a public debate on the bill, it had decided that there were other "tools" it could use to "protect Poland's good name".

"The change is a result of our analysis of the situation. Also, the international discussion, and especially in the United States had an impact. This is all connected," said a lawmaker from the PiS on the condition of anonymity.

Warsaw has been seeking security assurances from its ally the United States as a deterrence policy against Russia - and last month broke from the EU's outright rejection of Washington's withdrawal from the Iran nuclear deal.

European Union ministers began an unprecedented discussion on Tuesday of threats to the rule of law in Poland, urging Warsaw to step back from contested judicial reforms they say put its courts under more political control.

About 3 million Jews who lived in pre-war Poland were murdered by the Nazis, accounting for about half of all Jews killed in the Holocaust.

Jews from across the continent were sent to be killed at death camps built and operated by Germans in occupied Poland - home to Europe's biggest Jewish community at the time - including Auschwitz, Treblinka, Belzec and Sobibor.

Thousands of Poles risked their lives to protect Jewish neighbours during the war. But research published since the fall of communism in 1989 showed that thousands also killed Jews or denounced those who hid them to the Nazi occupiers, challenging the national narrative that Poland was solely a victim.