Labour’s Carwyn Jones and Plaid Cymru’s leader, Leanne Wood, have said they want “continued participation” in the EU’s trading bloc once Britain’s divorce is complete.
The pair, along with the Welsh Liberal Democrats, are responding to a historic speech by Theresa May last week, where she outlined her 12 principles for Brexit.
The prime minister vowed to pull out the country from the single market and ahlt the annual payments of “huge sums” into the EU budget.
Labour's Carwyn Jones wants Britain to remain in the single market after Brexit
We can leave the EU but that doesn’t mean we have to leave the single market
But, speaking on Radio 4’s Today programme, Mr Jones disagreed with Mrs May, claiming a vote to leave the bloc did not mean leaving the single market.
“For us in Wales we are very reliant on exports, particularly the farming industry, so it makes no sense to me that we should try to put barriers up between ourselves and our biggest market," he said.
In June’s referendum, Wales, like England, voted to quit the Brussel’s union with 52.5 per cent opting for Leave, slightly higher than the national figure.
The Welsh first minister said he "disagreed" with Theresa May's landmark speech last week
“We can still give affect to people’s views back in June. We can leave the EU but that doesn’t mean we have to leave the single market.
“I was in Norway a few weeks ago, they are not in the EU, but their relationship is very much in the single market,” he continued.
“The problem we have is we know people wanted to leave the EU, but no one is quite sure what the alternatives should be.
“This is our contribution to the debate and I believe this enables us to respect the result of the referendum, we’re not refighting that, but also provide a blue print, not just for the future of Wales, but for the future of Britain”.
The plan was written up along with Plaid Cymru's leader Leanna Wood
At that point, Today presenter Sarah Montague stopped Mr Jones and questioned whether his plan was respecting the result of the referendum.
On the defensive, Mr Jones responded: “We’re not trying to fight the result of the referendum.
“We now move on and see what sort of future and model will work for Britain and work for Wales."
Upon revealing their plan on Monday, the Welsh first minister billed the white paper as a “sensible starting point for negotiations that should deliver for all parts of the United Kingdom”.
In a joint letter in the Sunday Times, Mr Jones and Ms Wood stressed a need for a “fair and clearly understandable” immigration system.
They demanded funding received by Wales from Brussels for industries including agriculture must continue unaffected.
"We were told during the referendum that Wales would not lose a penny of its current funding as a result of leaving the EU and we intend to ensure that the UK government fulfils this promise," they wrote.
"We won't stand for Wales to be weakened as a result of Brexit, and believe that our plan is the best route to securing a good deal for our country."