The UK government has put forward proposed changes to the Brexit bill, despite a row with Welsh ministers.
The Welsh and Scottish governments have claimed the EU (Withdrawal) Bill amounts to a Whitehall "power grab".
After months of talks UK ministers have tabled amendments to the proposed law.
The UK government said the changes would strengthen devolution, but Welsh Finance Secretary Mark Drakeford said the amendments were simply a "fall back option" to protect Whitehall.
The EU (Withdrawal) Bill aims to ensure the rules currently set by European law still apply in the UK after Brexit, while giving the UK Parliament power to change them.
Under the current bill, without the amendments, powers in devolved areas that are currently wielded at EU level, such as agricultural support are set to return to Westminster rather than Cardiff, Edinburgh and Belfast.
Amendments to the Bill, which will need to be passed in the House of Lords, come after months of talks between the Welsh, Scottish and UK governments.
Last week UK ministers announced the list of powers that they would retain at a UK level, for a temporary period, including food labelling and agricultural support.
But an agreement has yet to be reached to finally resolve a row over who is responsible for what post-Brexit.
AMs and MSPs are due to vote on whether the bill should apply in Wales and Scotland.
Although the Welsh Government agrees to the need for UK frameworks in some areas, it has argued UK ministers should not constrain powers that are already devolved.
Welsh ministers have launched alternative legislation to retain EU rules in Welsh law in Cardiff Bay, but the UK government has said that is unnecessary.
Cabinet office minister David Lidington, who has been leading the talks, said the changes would "strengthen" devolution and protect the UK common market.
He said: "The amendments being tabled today will allow Parliament, businesses and consumers to better understand how we are intending to manage the transfer of powers from Brussels to the devolved administrations."
Mr Drakeford said he been left with the understanding there would be "further opportunities for talks" before the UK government put forward the amendments.
He said: "The Welsh Government has been very clear it would have been far preferable to have had amendments already agreed between the three governments before now.
"However, in my view, a UK government amendment at this stage does no more than protect its position, as a fall-back option, in much the same way as our continuity legislation does for the Welsh Government and National Assembly."
Last week Mr Drakeford said the UK government needed to make "significant changes to the Withdrawal Bill to fully respect devolution".
Plaid Cymru peer, Lord Dafydd Wigley said the UK government had showed "complete contempt" by bringing the amendments despite objections from the Welsh and Scottish governments.
Welsh Secretary Alun Cairns said he remained optimistic that an agreement between Westminster and Cardiff Bay would be reached to resolve the ongoing row.
He said that the UK government was not responsible for any delays and that he thinks anyone using the term 'power-grab' is "completely wrong".
"I didn't accept it in the first instance and I hope that the framework table that has been published demonstrates that's not the case," he said.
The First Minister of Wales, Carwyn Jones, and his Scottish counterpart Nicola Sturgeon will meet Prime Minister Theresa May in London for further talks on the legislation on Wednesday.