Bearder is also alleged to have claimed expenses for seeking legal advice she undertook after reportedly branding Danish MEP Morten Messerschmidt a Nazi.
On Tuesday, she told this website the allegations that she had tried to claim for the two items on expenses were "total nonsense."
Bearder, who is the only remaining British Liberal Democrat MEP, accepted that she had agreed to make a donation to Unicef as an apology to Messerschmidt.
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But she denied attempting to claim this on her parliamentary expenses, as was reported by the British media.
"There was an oversight but these allegations that have been made against me are nonsense," she said.
"Messerschmidt did threaten to sue me and, after this, I agreed to make a charitable donation. But I have nothing to apologise for because I have done nothing wrong."
It was reported that in a statement released by her office (since withdrawn), Bearder claimed the controversial Danish member had links to extreme right-wing groups.
After making the donation, Messerschmidt thanked her on Twitter, writing, "Happy that @CatherineMEP has withdrawn her slurs against me and my party; and happier that she has made a donation to UNICEF to apologise."
The Sun newspaper claimed Bearder, who was elected in 2009, tried to claim the donation and a separate bill for legal advice she had sought in the case against Messerschmidt on her parliamentary expenses.
The paper said it had obtained her 2014 expense claims which, it reported, showed how she wrongly claimed back the money for her legal advice, and the donation.
The UK based Taxpayers Alliance reportedly described the alleged expense claim as "disgraceful."
But, speaking to this website, Bearder robustly denied the allegations and pointed out that her expense claims were all published - and available for public scrutiny - online.
She said, "This is unlike a lot of MEPs, it has to be said."
A parliamentary source said that other than for day-to-day living costs and travel, MEPs should only claim for office management costs.
Messerschmidt has himself been at the centre of long running allegations of alleged financial irregularities after a fellow Danish MEP reported him to police, accusing him of identity theft in a case involving alleged misuse of EU funds.
Rikke Karlsson, a former member of the Danish People's Party, had accused Messerschmidt of using her name on official documents without her knowledge.
In 2016, Parliament demanded that Messerschmidt repay around €400,000 of EU funds after auditors Ernst & Young found that 2015 statements from the affiliated Foundation for a Europe of Liberties and Democracy did not give a true picture of their financial situation and that "fundamental information" was missing from the financial documents.