The former Green leader Caroline Lucas has called for the party to take immediate action against candidates who have made antisemitic comments or posts, following a series of cases before Thursday’s elections.

Lucas, who led or co-led the party for six years and served as its first MP, said that while the number of such cases was limited, they could not be ignored.

“Statements that have now come to light from a handful of @TheGreenParty candidates are totally unacceptable & require immediate action,” she wrote on X. “There’s no place for antisemitism or any hate speech in the party. This is a society-wide problem and needs to be rooted out wherever it’s found.”

Zack Polanski, who now leads the Greens in England and Wales, has disowned candidates highlighted for antisemitic comments. However, Labour has accused the party of acting too slowly to suspend or remove them.

The issue was highlighted last week after two Green candidates for Lambeth council in south London, Sabine Mairey and Saiqa Ali, were arrested on suspicion of stirring up racial hatred online.

Screenshots of Ali’s Instagram account indicated she had posted an image of an armed man wearing a headband of the banned Islamist group Hamas, along with the slogan: “Resistance is freedom”.

Another screenshot indicated that Mairey had shared a post which included the text: “Ramming a synagogue isn’t antisemitism. It’s revenge.” Both have been suspended by the party.

Among other cases, the Greens are investigating Brian Capaloff, a candidate in Waltham Forest, north-east London, over allegations he posted on X using an anonymous account to speculate whether last week’s stabbing of two Jewish men in north-west London had been deliberately staged by Zionists.

Also under investigation is Joe Belcher, a candidate in Walsall. He was suspended by the Greens when running for a West Midlands parliamentary seat in the 2024 election after posts emerged in which he suggested Hamas might have been paid by Israel to carry out the 7 October 2023 attacks.

Under the Greens’ highly decentralised system, local parties have considerable power, including over who they select as candidates. The party argues this can make it slower to suspend candidates than is often the case for other parties.

Speaking to the BBC on Sunday, Polanski condemned any antisemitic comments, saying this was “not an abstract idea” for him. “As a Jewish person, those comments disgust me. It’s important that we let the disciplinary process take its place, and that’s exactly what we have,” he said.

He rejected the idea this was something especially prevalent in the Greens: “I don’t believe we have a particular problem compared [with] wider society and other political parties.”

Polanski said he disowned candidates who had made such comments. Asked if he would “tell people here today: don’t vote for them, they don’t stand for you”, he replied: “That’s right.”

A Green spokesperson said: “Caroline Lucas is right – there’s no place for antisemitism or hate speech in any party. She acknowledges that unacceptable comments have been made by just a small number of the 4,500-plus Green party candidates in these local elections.

“Where there are examples brought to our attention that do not align with the values of the Green party, we are looking into them, and in some cases candidates have already been suspended. We are investing in strengthening our vetting procedures to prevent inappropriate candidates slipping through the net.”