Nigel Farage has been accused of having shoved a female Liberal Democrat MP earlier this year, after he spoke about missing this week’s budget because of a previous altercation about seating.

The Reform leader said on Wednesday that he skipped John Healey’s speech in the House of Commons due to his seat reservation having been moved.

He claimed that he had been involved in a “physical altercation” with another MP on the day of the state opening of parliament in May, so he decided to give it a “wide berth” in order to “avoid conflict” in the chamber.

It later emerged his reservation had been removed by Commons staff as it did not have the proper date stamp.

However, the row then escalated as Daisy Cooper, the Lib Dem deputy leader, claimed that her party’s MPs were involved in the May incident mentioned by Farage.

Cooper told Sky News: “My understanding – I didn’t see it, I wasn’t there – but my understanding is that he physically shoved one of our female MPs out of the way, and that one of our male MPs then challenged him on that.

“I didn’t see it, I didn’t witness what happened, but that was several months ago.

“And let’s be really clear: it’s Reform UK that had a problem at their conference with bundling female journalists and members out of their hall. So, we’ll take no lessons from them on this.”

The Lib Dem MP involved in the incident is believed to be Caroline Voaden, who posted on social media: “We both know that’s not true Nigel don’t we?

“I’m still waiting for the apology you were required to write to me … Though I won’t hold my breath.”

Related: Nigel Farage skips budget in Commons over seating ‘altercation’ concerns

A Reform source told the Telegraph they disputed the Lib Dem characterisation, saying: “It’s not true at all – it was the Lib Dem MPs being aggressive towards Nigel. This is typical Lib Dem dishonesty in an attempt to stay relevant.”

When asked for a response to the accusations, Robert Jenrick, Reform’s shadow chancellor, said: “You know what? I am sick to death of these pathetic Westminster debates.

“The thing about Reform politicians is, yeah, we love parliament, the institution of parliament. I go there every day. I speak in parliament. I represent my constituents.

“But I’m much more interested about, actually, the issues, trying to change this country, getting out and about outside of the bubble. And I’m not interested in even responding, dignifying the nonsense that Daisy Cooper is talking about there.”

Reform has been approached for comment.