The First Minister Mark Drakeford has criticised the UK Treasury over what he believes is a lack of transparency.
Mark Drakeford said the Treasury needed to adopt "greater accuracy and transparency" over the way announcements are made and criticised it for making decisions at the 11th hour.
Last week the Chancellor, Rishi Sunak, said the Welsh Government would receive £227 million of additional business support as England entered a third lockdown.
However, it later emerged the funding was part of the £5.2bn already guaranteed to Wales since the beginning of the pandemic.
Mr Drakeford told the Senedd: "The UK Government continues to make funding announcements at the 11th hour without any engagement with the devolved governments, without any immediate clarity on the implications for Wales.
"Confusion surrounding last week's announcement on business support is only the latest example."
Labour MS Dawn Bowden drew the First Minister's attention to the social media accounts of the Welsh Conservatives which said the UK Government was providing £220 million of "extra funding".
"Have we in fact been told one of the most misleading and dishonest statements ever told by the Welsh Tories?," she asked.
The First Minister replied: "The Treasury made an announcement and I heard it myself on the radio that there was an extra £227 million coming to Wales.
"I thought that was very good news we would have been able to use it to top up the most generous package of support for businesses anywhere in the UK.
"Then it turned out a few hours later that this wasn't extra money at all, and we had it already.
"That really isn't the way to conduct business across the UK nations."
Mr Drakeford told the Senedd the Welsh Government would publish a further supplementary budget in February.
"This will be the third time Senedd members will have had a chance to see how the Welsh Government is using the money that is available to us in this extraordinary financial year," he said.
"The UK Government has not published a single supplementary estimate in the whole of this financial year.
"I think the member makes a very good point about the importance of being clear with people, where the money is coming from and what it's been used for.
"We try and do that here in the Welsh Government and we would have been helped over this issue if there had been some greater accuracy and transparency in the way the UK Government describes the money which, in the end, did not come at all to Wales."
The UK Government said the funding announcement was part of the Barnett guarantee, which is designed to set out how much additional funding the UK Government will provide to each of the devolved administrations to address the pressures of the pandemic in 2020-21.
It works by providing money upfront to the devolved nations, rather than working in the traditional way of giving them Barnett formula funding once funding specifically for England had been announced.
In an exchange in the House of Commons on Monday Rishi Sunak, the Chancellor, in response to a statement from Gower MP Tonia Antoniazzi, said "it was right" that the Government highlighted the amount of additional funding stemming from the Barnett guarantee.
He said: "I am happy for the hon. Lady to refer to the answer I gave earlier, but if she would prefer that, rather than give up-front funding guarantees and certainty to the devolved Administrations in a pandemic, we returned to piecemeal funding by announcement, she should please write to me and let me know.
"The Welsh Government have received over £5 billion in up-front funding guarantees, and as we make announcements it is right that we highlight the amount of additional Barnett funding that flows from those announcements, so that that can be netted off against the guarantee.