Stephen Flynn mocked Rishi Sunak by asking if it hurt that "Labour believes in Brexit more than he does" during Prime Minister's Questions on Wednesday.
The SNP leader at Westminster was referring to the PM's comments the yesterday that Northern Ireland was "in an unbelievably special position" and was "privileged" as it had access to both the EU and UK markets.
Sunak agreed a deal with the EU on post-Brexit trading arrangements for Northern Ireland on Monday.
The new deal means that Northern Ireland has access to both the UK market and the EU single market.
But Flynn suggested that Sunak's comments were pro-EU, while Labour has been clear that it does not want to return to the EU or the single market.
Flynn said: "What the Prime Minister said yesterday was that EU single market access will be a good thing for business.
"Of course that's in contrast to the leader of the Labour Party who said in December that EU single market access would not boost economic growth.
"Does it hurt the Prime Minister to know that the Labour Party believe in Brexit more than he does?"
Sunak replied: "With regard to Northern Ireland, the important thing to note is to avoid a land border on the island of Ireland between North and South.
"That is what is crucial to achieve in getting the right framework for their arrangements in Northern Ireland and the businesses there that trade across that border on a daily basis with complex supply chain need and value that access.
"That is something that the Windsor Framework has sought to achieve and I believe delivers it.
"It's not about the macro-issue of membership of the European Union. It's about getting the right mechanisms in place to support businesses and communities in Northern Ireland.
"And I would say to the honourable gentleman: he knows better that. He knows that this is about Northern Ireland and I hope that he can support what we've agreed."
A Labour spokesman responded after Prime Minister's Questions: "We've been very clear on this. There is no return to the single market no return to the Customs Union no return to freedom of movement that has been our position.
"We have also set out ways in which the Brexit deal can be improved."
He added that Northern Ireland had "unique circumstances" and that Labour would not let Scotland have similar access to the single market.
The SNP had already written to the Prime Minister asking for Scotland to also be treated the same as Northern Ireland.
Flynn also asked Sunak why he was stopping the country from having EU membership if it was so positive for Northern Ireland.
He said: "Yesterday, the prime minister said that EU single market access was 'special', 'exciting' and 'attractive'.
"If that's the case, why has he denied it to the rest of us?"
Sunak replied: "It's disappointing [that] the honourable gentleman is seeking to play politics with the situation in Northern Ireland.
"Northern Ireland, as he well knows, has a unique place in the United Kingdom and what we are trying to do is restore the balance inherent in the Belfast Good Friday Agreement. And he would do well to acknowledge that."
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