Theresa May has rejected claims her government is involved in a Brexit "power grab" from the Welsh Government.
The prime minister told senior MPs more powers would go to Cardiff after Britain leaves the EU next year.
Mrs May sidestepped a question on whether she would try to overrule a new "continuity" law passed by AMs designed to "protect" the devolution settlement.
She said she thought there was "genuine intent" to resolve a row between UK ministers and devolved governments.
The dispute with administrations in Wales and Scotland is over what happens to European powers in devolved areas such as farming and environmental protection.
Appearing before the Commons Liaison Committee, the prime minister said there was goodwill on both sides - "we're edging closer and closer" - but further discussions were needed.
She said the priority was to maintain the UK's internal market.
A bill to transfer EU law into UK law is currently going through the House of Lords and Wales' First Minister Carwyn Jones has said that time is running out to reach an agreement.
The claims of a power grab, made by the Welsh Government, were raised by the chair of the Welsh Affairs Committee, Conservative MP David Davies.
He asked: "Could you just confirm that there's not a single thing that the Welsh Government can do today that it won't be able to do once Brexit has taken place?"
Mrs May replied: "Absolutely. We're not taking any powers back from the Welsh Government or indeed the Scottish government.
"What we're talking about is devolving more powers to the devolved administrations but it's also about making sure that people are able to continue to trade and do business and operate in the UK internal market as they do today."
Mr Davies said: "I'm actually surprised at how many extra powers are going to the Welsh Government but that's another matter."
But the SNP chair of the Scottish affairs committee, Pete Wishart, told the prime minister the way the UK government had tried to resolve devolution issues was "contrary to everything devolution is about".
Mr Wishart asked if the UK government was ruling out the principle of consent, and if it would be overruling continuity bills passed in Wales and Scotland.
Mrs May said the "answer should be in coming to an agreement", and in her view it wasn't necessary for continuity bills to be passed.
Questioned about farming after Brexit, the prime minister joked about her decision to call last year's general election while hill-walking in Snowdonia.
"I do recognise the importance of Welsh agriculture. I'm tempted to point out that I do see the value of Welsh agriculture to the Welsh landscape quite often when I go walking in Wales although given the decision I took last year I'm not sure that many would welcome my reference to walking in Wales again."