The Prime Minister's Brexit agreement is a "bad deal" for Wales, "failing to give Welsh people the certainty needed to safeguard jobs and livelihoods", the shadow Welsh secretary has argued.
Christina Rees claimed the term "frictionless trade" did not appear in the Government's political declaration, adding that the Withdrawal Agreement "does not even mention Wales".
But Secretary of State for Wales Alun Cairns hit back, arguing that Theresa May's deal "gives the certainty of access to the EU markets but it also gives us the new opportunities to strike trade deals around the world".
He added: "I'm optimistic about our prospects outside the EU, I wish that optimism was shared elsewhere."
Speaking at Commons Wales questions, Ms Rees said: "The Secretary of State has given his backing to an agreement that does not even mention Wales let alone protect workers' rights, environmental standards, consumer protections and living standards.
"Isn't the reality that this is a bad deal for Wales, failing to give Welsh people the certainty needed to safeguard jobs and livelihoods?"
Mr Cairns replied: "The deal that the Prime Minister has negotiated gives the certainty of access to the EU markets but it also gives us the new opportunities to strike trade deals around the world. I would say to her, I'm not sure what certainty a further referendum would bring, if that is her policy."
He added: "The Government's analysis shows that Government has negotiated the best deal available for Welsh jobs and the Welsh economy that allows us to honour the referendum and realise the new opportunities Brexit will bring."
Labour's Chris Elmore (Ogmore) said the viability of manufacturing relied on frictionless trade with the EU, adding: "The Prime Minister's deal gives us no assurances to Welsh businesses just buzzwords and more uncertainty."
His colleague, Owen Smith (Pontypridd), argued that Wales was going to be poorer and its GDP smaller if MPs voted for the deal.