Labour MPs and peers are planning an extraordinary joint act of defiance against Jeremy Corbyn and the party’s ruling national executive committee (NEC) that would see them incorporate the full internationally accepted definition of antisemitism into their own official rulebooks, putting them directly at odds with the party leadership.

The moves by Labour members of both Houses of Parliament look set to fuel an already explosive row that erupted last week, after the NEC refused to ditch a controversial new code of conduct on antisemitism that many MPs and peers say does not go far enough.

In the hope of forcing the NEC and party leadership into a U-turn, Labour MPs will on Monday push an emergency motion at a meeting of the parliamentary Labour party that would, if passed, amend its rulebook to include an obligation on members “to accept and abide by the full International Holocaust Remembrance Alliance working definition of antisemitism, including all of its accompanying examples”.

Separately, the Observer has learned that Labour members of the House of Lords will be asked to vote when parliament returns in September on a motion to alter the Labour peers group handbook so that it also includes reference to the need for members to abide by the full IHRA definition.

In an email, the chair of Labour members of the House of Lords, Toby Harris, said he was sure colleagues would share his “deep concern at the Labour party’s failure fully to adopt the International Holocaust Remembrance Alliance definition of antisemitism”.

He said that “following consultation with the Labour Lords leadership … I will be proposing from the chair that we adopt the IHRA definition and its associated examples – unamended – into our rules [the Labour peers group handbook]”.

The new party code of conduct has been widely criticised because it fails to incorporate all the examples of what constitutes antisemitism that are listed alongside the IHRA definition.

The examples omitted from the new Labour code agreed by the NEC include accusing Jewish citizens of being more loyal to Israel than their own nations, claiming that the existence of the state of Israel is a racist endeavour and comparing Israeli actions with those of the Nazis.

The decision by the NEC last Wednesday to adopt the new code came despite complaints and warnings from members of the parliamentary Labour party and Jewish organisations urging the ruling body to include the full list of examples.

The emergency motion to be submitted to the PLP has been tabled by the Jewish Labour MPs Louise Ellman and Ruth Smeeth. They are backed by another Jewish member, Luciana Berger. Berger, parliamentary chair of the Jewish Labour movement, said she expected the motion would be accepted for debate and voted upon when time allowed. “Its purpose is to demonstrate the strength of feeling in the parliamentary party. It is unfathomable that we find ourselves in this position as a party,” she said.

After the NEC decision, Labour minister and ex-chair of the public accounts committee Margaret Hodge confronted Corbyn in the House of Commons and accused him of being “an antisemitic racist”. She is now the subject of a party investigation.

Facebook Twitter Pinterest Labour leader Jeremy Corbyn has been criticised for not rooting out antisemitism in the party. Photograph: David Hartley/Rex

A Labour party spokesperson said that while the code had been adopted, it would be subject to further discussion in the light of strong feelings expressed: “The NEC upheld the adoption of the code of conduct on antisemitism but, in recognition of the serious concerns expressed, agreed to reopen the development of the code, in consultation with Jewish community organisations and groups, in order to better reflect their views.”

On Saturday night the Labour MP Wes Streeting said he believed the NEC had taken the approach it had so that it would be easier for the party to reject complaints made against members over antisemitism.

“It is hard to draw any other conclusion than that this is intended to make it easier to let more people off the hook, whether they be new members of the party or senior figures within it.”

On Saturday, in an interview with the Guardian, Eddie Izzard urged Corbyn to deal promptly with the issue. The comedian, who recently won a seat on the NEC, said Labour risked not being ready to attack the government and its Brexit plans because of infighting over antisemitism.

“We shouldn’t be getting caught in this antisemitic definition row,” Izzard said. “If there is ever a time to adopt the full IHRA definition and be in step with the Jewish community, the rabbis, go with the mainstream, rather than say we wish to adjust, that meeting was the time. And we didn’t.”

He said Labour had agreed to reopen discussions with Jewish groups, but that he regretted that a new code of conduct had been approved despite warnings from Jewish groups about the omission of some of the working examples from the IHRA.