Ukip’s only MP made the claim while a BBC panel discussed the effect of potential immigration rule changes on British industry.
Speaking on BBC Radio 4’s Any Questions?, Mr Carswell insisted there was a difference between the free movement of “people” and “workers”, adding it was “important” to recognise migrants who have contributed to Britain.
He said: “I think it is really important to make sure we recognise and respect those who have come here to make a contribution, and I think it’s imperative for people like me in parliament to speak out in favour of the positives that immigration brings.
“When I talk about the need for us of having a ‘liberal’ Brexit, I mean it is important that despite leaving the European Union we have a system of migration that allows people who want to come here to make a contribution to do it.
Douglas Carswell called on Britain to adopt a 'liberal' Brexit
It’s imperative for people like me in parliament to speak out in favour of the positives of immigration
“But, we as a country decide who comes and on what conditions.”
Mr Carswell added: “It’s all about control, and it is important that people understand there is a fundamental difference between two phrases that sound similar: free movement of workers and free movement of people.
“At the moment we have free movement of people, that means anyone who is an EU nation in one of the other 27 member states can come here.
“That was a consequence of the Maastricht Treat, and that has to go.”
His views come in contrast to research conducted by Economists for Free Trade, who have called for end of a stream of unskilled migrants entering the country.
Their research shows each person coming to the UK without any skills costs taxpayers an average £3,500 each year in welfare and support.
The lobby group is arguing for a post-Brexit visa system, which promotes immigration of skilled workers.
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The Economists for Brexit co-founder, Gerard Lyons, has claimed the freedom of movement within the EU is “discriminatory” to workers from outside the bloc.
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He said it was in the UK’s “best interests” to limit migration and adopt an alternative visa or quota system for specific sectors.
He told Express.co.uk: “It’s vitally important that we think this through properly. Before, we had a very strange migration policy – it was unlimited in terms of EU workers and sort of discriminatory towards those from outside the EU.
“The way we need to think about it is ‘what migration policy is in the best interest of the country from its national perspective and that will limit the scale of migration?’
“But it should not affect how the economy performs.”