Labour faced fresh controversy over its policy on antisemitism on Saturday after it emerged that a second MP who has criticised the party’s new code on the issue may face disciplinary action leading to suspension from the party.

Ian Austin, whose adoptive parents were Czech Jewish refugees who lost relatives in the Holocaust, was sent a letter earlier this month from the party’s head office warning that he was being investigated for “abusive conduct” in parliament.

The MP for Dudley North had clashed with the Labour party chair, Ian Lavery, in the House of Commons just before the parliamentary recess in a heated exchange that was witnessed by other MPs.

Austin was angry about the party’s new code, which recognises the internationally accepted International Holocaust Remembrance Alliance (IHRA) definition of antisemitism but does not replicate in full its list of examples – a contentious omission that has dismayed many within the party and further strained Labour’s relations with the Jewish community in the UK. Jewish newspapers joined together last week to jointly attack the party’s decision on the IHRA code, which the party has said it would review in the autumn.

The letter sent to Austin is identical to one sent a day before, on 18 July, to the veteran Labour MP Margaret Hodge, who was told that she faces disciplinary action for abusive conduct, having branded Jeremy Corbyn a “racist and antisemite”.

It informed Austin: “You should be aware that any future behaviour of a similar nature to the allegation above could result in further disciplinary action, including the possibility of administrative suspension while the matter is investigated.”

Austin told the Observer: “Wouldn’t it be great if they dealt with the people responsible for racism as quickly as they dealt with the people who are understandably upset about it? I am angry about antisemitism and I am angry that the Labour party can’t deal with it adequately.”

A senior figure in the British Jewish community said: “It looks like a full-scale purge.”

But a Labour party spokesman defended the action to investigate allegations of abusive behaviour among its members. “The Labour party takes all complaints extremely seriously,” he said. “These are fully investigated in line with party rules and procedures.”

The toxic row over its antisemitism code is threatening to engulf Labour.

On Friday it moved swiftly to suspend a councillor who has been accused of calling for Jews to be “executed”. Damien Enticott, who sits on Bognor Regis town council, denied making the claims, saying his Facebook page had been hacked.

But questions continue to dog the Labour leadership about the messages it is sending out to the party’s membership. Critics have seized on comments made by Corbyn in 2012 when appearing on Press TV, the Iranian state-owned broadcaster, in which he linked a jihadi massacre of 16 Egyptian policeman to Israel.

Corbyn said: “I’m very concerned about it [the massacre] and you have to look at the big picture: in whose interests is it to destabilise the new government in Egypt? In whose interest is it to kill Egyptians, other than Israel, concerned at the growing closeness of relationship between Palestine and the new Egyptian government?”

During the attack, masked gunmen dressed as Bedouin nomads opened fire on police with guns and rocket-propelled grenades, Egyptian state television reported. Sixteen soldiers and border guards were killed and another seven were wounded, officials said at the time.

Jeremy Corbyn is interviewed by Lauren Booth on the Iranian state-owned broadcaster Press TV. Photograph: Press TV

The Press TV presenter Lauren Booth asked Corbyn: “Would a Muslim go against his Egyptian brother and open fire?”

Corbyn responded: “It seems a bit unlikely that would happen during Ramadan, to put it mildly, and I suspect the hand of Israel in this whole process of destabilisation.”

The previous year Israel had conceded that several Egyptian police officers might have been killed accidentally by Israeli fire during an incursion by Palestinian militants.

“Jeremy’s speculation about the perpetrators of the attacks on the Egyptian border guards was based on previous well-documented incidents of killings of Egyptian forces by the Israeli military,” a Labour party spokesman said.

Ivor Caplin, chair of the Jewish Labour Movement, said: “Conspiracy theories underpin a huge swathe of antisemitism. Grand conspiracies about Jews, either individually or as a collective, are antisemitic. The IHRA definition is clear about this. This is why Labour should have adopted the definition in full, including all of the examples. Jeremy needs to provide clarity on his views on this conspiracy theory and any others he may have aired in the past.”

Dave Rich, head of policy at the charity Community Security Trust, said: “The debate about the IHRA definition and Labour’s code has been about the difference between clear antisemitism and criticism of Israel, but often the problem comes with an extreme hatred of Israel, often expressed through conspiracy theories that provide the bridge between the two.”