Speaking to Andrew Marr this morning, Brexit secretary David Davis claimed the story was "nonsense" and "completely wrong".
"What he's [Barnier] concerned about of course is he's not getting the answer on money and they've set this up to try to create pressure on us on money", Davis said.
While there was "no enforceable" legal basis for the United Kingdom to pay money to Brussels, Mr Davis said, "we are a country that meets its global obligations - but they have got to be there".More news: Wenger: Lemar Rejected Arsenal, But We Will Try Again
Later, Mr Davis insisted he was not branding Mr Barnier personally "silly", adding: "I said the commission would make itself look silly". "It takes the laws that are there now and puts them in place the day after we leave".
The British government has been keen to shift talks to a new relationship, seeking to allay business concerns on trade and regulation, but Brussels has demanded progress first on central issues, including how much Britain should pay when it leaves.
"Money is incredibly important, it is the thing that frightens them most", he said on the BBC's Andrew Marr show.
On the same programme, he denied reports that British Prime Minister Theresa May would accept a €5o billion Brexit fee, adding that the United Kingdom were under no legal obligation to pay the fee - whatever the amount is.More news: Britain says it can not be blackmailed by European Union over exit bill
"The more and more time we lose in the coming months, the more and more it is clear that the transition period can only be the prolongation of the existing situation, the status quo", Verhofstadt told legislators.
Mr Barnier continued the sniping at Britain yesterday, telling a conference in Italy that Brexit would be an "educational process" for the United Kingdom because Brits do not realise what they have to give up. "They may not be legal ones, they may be moral or political ones", he said.
The first debate on the so-called Repeal Bill, which ensure European Union law will no longer apply in the United Kingdom, takes place on Thursday, and the Prime Minister has warned would-be rebels in her party not to water down the legislation. "[The Europeans] won't talk about the future, they'll only talk about so-called divorce proceedings".
"We meet worldwide obligations - also want to leave in orderly and smooth manner and in order to do that it's best to leave on amicable terms, on proper terms on negotiated terms and don't just walk away", he added. "Starting the new parliamentary session with the withdrawal bill shows that it is now the job of all MPs, including my former colleagues on the Stronger In campaign, to respect the will of the people and get the best possible deal for Britain", he said. If you want a "soft" Brexit - and I don't actually deal with "soft" and "hard" Brexit, I want a effective successful and Brexit - but if you want something like continuity this is the bill you should be supporting.More news: Virat Kohli hits 30th ODI century, joint second highest in cricket history