The first minister of Wales and Plaid Cymru's leader have published a plan for Brexit, calling for freedom of movement rules to be linked to whether migrants have a job.
The white paper, launched by Carwyn Jones and Leanne Wood in London, demands full single market access.
Ms Wood said on Monday that free movement was "not a problem".
UKIP's Neil Hamilton dismissed the Labour/Plaid white paper as a "white flag of surrender" to the EU.
Last week, Prime Minister Theresa May said the UK should leave the single market as she outlined her 12 principles for Brexit.
Mr Jones said the plan respected the Welsh vote to leave the EU but would give the UK "full and unfettered access" to the single market.
He said freedom of movement rules could require EU migrants to have a job offer before entering the UK, adding UK legislation could be enforced to stop workers being exploited.
"Our plan explains how we can strike a balance between the message the Welsh people gave us with the economic reality that we face," he said.
According to the paper, 79% of EU migrants aged 16-64 in Wales are in employment.
The Welsh Government white paper called for:
- Continued participation in the single market to support "the future prosperity of Wales"
- A balanced approach to immigration linking migration to jobs, with "properly-enforced" employment practices that protect all workers
- For the UK government to make good on promises that Wales would not lose funding as a result of Brexit
- A "fundamentally different" relationship between the devolved governments and the UK government
It also called for social and environmental protections; for workers' rights to be maintained; and for transition arrangements to be properly considered so the UK does "not fall off" an economic "cliff edge".
Ms Wood said that, in engaging with the process of drawing up a plan, Plaid Cymru had "prioritised the Welsh economy".
"We have done this because two thirds of all of our exports go to the European single market," she said.
Speaking on BBC Radio 4's Today programme on Monday, Mr Jones said it made "no sense" to place barriers between Wales and its biggest market.
The document follows an agreement between Labour, Plaid Cymru and the Liberal Democrats.
UKIP Wales leader Neil Hamilton dismissed the proposals, saying: "It's not so much a white paper as a white flag of surrender to the EU before negotiations have actually started.
"If Theresa May were to take this blueprint to Brussels then the EU would get everything they wanted.
"It would mean that we weren't leaving the EU in any meaningful sense at all."
Nathan Gill, UKIP Wales MEP, said the paper proved "just how out of touch the political elite in Cardiff Bay are with the majority of Welsh voters".
"The latest YouGov poll released at the beginning of this month showed that the majority of Welsh voters want full control over immigration," he said.
"The only way to control the quantity and quality of people coming to Britain is to leave the single market."
Welsh Conservative leader Andrew RT Davies said he would have tried to reach a wider cross-party agreement but claimed the first minister had not invited him.
"We have a disorganised message coming from Wales," he said, adding Europe also needed to respond on the issue of immigration.
"When the single market was created and the tenets that underpin the single market, this mass movement of people around Europe wasn't a consideration," he said.
"It is a consideration today."
Mr Davies told BBC Radio Wales that, given Scotland had tabled a paper at the joint ministerial committee on Brexit last Thursday, the Welsh Government plan was "a bit late in the day".
But the first minister has defended the decision to publish the plan a week after Mrs May set out the UK government's objectives, saying the Welsh plan was more detailed and comprehensive.
The leaders' launch comes ahead of the expected decision by the Supreme Court on Tuesday on whether Parliament should have a say before Article 50 is invoked.