A model which could see the UK remain in the single market after Brexit would be "very difficult for people to accept", a former shadow Europe minister has said.
Caerphilly MP Wayne David said the Norway model, favoured by First Minister Carwyn Jones, would lead to a "massive loss of sovereignty".
He said the Labour party needed to have a debate on its Brexit position.
Mr Jones' spokesman said single market access was key to protecting jobs.
Norway is not in the European Union but it still has access to the single market.
It has to make a financial contribution and must accept the majority of EU laws but it does not have a say on how they are created.
First Minister Carwyn Jones visited Norway in January to learn about its EU links and said the example demonstrated the UK did not have to give up access to the single market when it leaves the European Union.
Speaking on Monday, he said: "We would not control the rules but we would have full and unfettered access."
Mr David said although the first minister was right to focus on the importance of the single market - with many Welsh jobs dependent on it - the Norway model was a step too far.
"The big problem with simply adopting the Norwegian model is that we accept the laws which are made in the European Union, which we will be outside, without having any say on those laws as they affect the single market," he said.
"That is a big pill for people to swallow.
"It is very difficult for people to accept that for the first time in our history a large measure of our legislation will be made by other people and yet we will be having to conduct all our business relationships under those laws."
Mr David said the the UK could look at how elements of the Norway Model could work in part, rather embracing it "hook, line and sinker".
A spokesman for the first minister said: "We have consistently argued that protecting jobs and our economy should be the focus of Brexit negotiations.
"The most effective way of doing this is through securing full and unfettered access to the single market and remaining in the customs union as we set out in our Brexit white paper.
"Membership of the EEA is one option for maintaining full and unfettered access, as Norway do, though it is not the only model."
Labour's shadow international trade secretary Barry Gardiner has already said the Norway model would prevent the UK from achieving the reasons why people voted to leave the EU.