Zarah Sultana has boycotted the first day of Your Party’s inaugural conference, throwing the party’s first official gathering into chaos amid disagreements with co-founder Jeremy Corbyn over how the party should be run.

Corbyn confirmed to journalists on Saturday that he preferred a single leader and is likely to stand for the role but Sultana said she would vote for collective leadership and that she did not believe parties should be run by “sole personalities”.

In a sign of further division within the fledgling movement, a spokesperson for Sultana said she would not be entering the conference hall on Saturday in solidarity with delegates who were expelled over links to other leftwing parties, describing the process as a “witch-hunt”.

The Guardian understands Sultana will run against Corbyn if members decide to elect one leader. Delegates in Liverpool will choose between electing a sole leader or a collective of lay members – those not already serving as MPs or councillors.

The party has been beset by infighting since plans for it were first announced in July after Sultana announced her defection from Labour, saying she and Corbyn would co-lead a new political organisation. Allies of Corbyn were quick to brief that a final decision had not been made.

The pair appeared to strike a fragile peace, with Sultana likening their relationship to that of Noel and Liam Gallagher. Corbyn said on Saturday that he would “probably favour the single leadership model” but would “live with whatever [members] decide on”.

However, her decision to skip the first day of proceedings is likely to go down badly with Corbyn and his aides. It is understood that one of her supporters, James Giles, a councillor in Kingston, was barred from entering the conference centre. Other members were expelled on Friday over alleged membership of the Socialist Workers party.

Corbyn told journalists on Saturday that entry to Your Party was granted on the condition members were not aligned with other parties registered with the Electoral Commission.

He added: “The Socialist Workers party is registered with the Electoral Commission, therefore it is another party. I think to call it a purge is a bit of exaggeration quite honestly.”

A spokesperson for Sultana said: “Zarah met members outside conference and condemned the recent expulsions. This witch-hunt is indefensible. We must build a party that welcomes all socialists.

“She will not be entering the conference hall today.” It is understood Sultana will attend the conference on Sunday to deliver a planned speech.

A Your Party spokesperson said: “These claims are false. Members of another national political party signed up to Your Party in contravention of clearly stated membership rules – and these rules were enforced.”

Speaking before Sultana announced her boycott, Corbyn had hinted to journalists that he was ready to stand as leader in a contest. “I’m very happy to serve the party in whatever capacity they decide they want me to serve,”he said.

Sultana said she supported collective leadership in the absence of the option for two co-leaders. She said: “I’ve publicly supported a co-leadership model. The fact it hasn’t been given to members as an option to vote on is regrettable, and the fact that has been decided by a faceless, nameless bureaucrat is quite concerning.”

She said she was “championing collective leadership” because she felt it offered “maximum member democracy”.

“I don’t think movements should be led by sole personalities. I think you have to represent the broad mass movement,” she said. “That allows responsibility to be shared and more people’s ideas to be listened to. It strengthens the movement. With that, comes a structure which has a parliamentary convener. They are also elected by the membership.

“Should the members choose sole leadership, I would consider throwing my hat in the ring. I will then respect whatever the members decide and completely ride in behind that.”

Corbyn and Sultana said they would consider electoral pacts with other leftwing parties, including the Greens.

Sultana said: “I think we have to work with the Greens and other parties so we can stop Nigel Farage getting into Number 10. That has to be the guiding principle for all of us who want to stop fascism.”

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Corbyn said it “would essentially be a decision for the local branches of Your Party” to judge what was best in their area, but he that he would not rule out cooperating with the Green party, which has enjoyed a rise in popularity under its new leader, Zack Polanski.

Tensions between Corbyn, the former Labour leader who is now an independent MP for Islington North, and Sultana, who represents Coventry South, escalated when Sultana launched a membership portal, collecting about £800,000 in donations and reams of members’ data.

Sultana said on Saturday that £600,000 had already been transferred from a holding company to Your Party and that the remainder of the money would be sent when liabilities had been processed.

She said she was now getting on “really well” with Corbyn and that the pair had been communicating about the conference, which she said they wanted to be “a positive, joyful experience where members feel empowered”.

However, tensions between Sultana and key allies of Corbyn persist. Relations with his former chief of staff Karie Murphy are believed to be particularly strained.

Sultana admitted there was still a “toxic culture” in Your Party, which had led to “bullying, intimidation and smears” and “acts of deliberate sabotage”.

She said: “I can definitely say that toxic culture I’ve experienced needs to be rooted out. I would say that is directly from the handbook of the Labour right. It’s shocking to experience in a new leftwing, socialist party. We do need to dismantle that culture.

“I think there are people who are around Jeremy – not Jeremy himself – who have learned the wrong lessons from their time in the Labour party, where they have been on the wrong end of smears, of sabotage, attacks in the rightwing press … they are now using the same tactics when really we should have a healthy climate of being able to debate and disagree.”

In his speech on Saturday, Corbyn called for unity. “As a party, we’ve got to come together and be united, because division and disunity will not serve the interests of the people that we want to represent,” he said.

He also called for “public, democratic ownership” of the water industry, led a chant of “free, free Palestine” and urged party members to “campaign forevermore for real socialism and real social justice”.