Peterborough MP Stewart Jackson has reassured migrant workers that they are still welcome in the city.
Mr Jackson, who is the Parliamentary Private Secretary to the Secretary of State for Exiting the European Union, made his comments to city business people during a question and answer session on Brexit.
He told the gathering of about 40 people that business leaders had to tell government how many people they needed from overseas and they type of qualifications they required.
He said: "We need data from businesses
"We will continue to get people from overseas to come here to work business must quantify its needs."
Mr Jackson said membership of the EU currently hampered the UK's ability to make value judgements about the type of people that should be allowed into the country.
But a number of people voiced concern at the lack of reassurances for overseas workers in the UK who were worried they might be asked to leave the country.
Iain Forsythe, managing director of Premier Kitchens and Bedrooms, of Peterborough, warned that without reassurances that they are welcome, some people were already being "poached back by their motherlands".
Others said that many overseas people were feeling vulnerable and some were actively looking to leave.
Mr Jackson said: "It would be crazy to reject people, who have lived here, have their families here and are making a contribution to the local economy.
"The difference is that after Brexit we will have more control over immigration in a way that we have not had before."
During the hour-and-a-half session at the Key Theatre, in Peterborough, questions ranged from issues around people and skills, money, trade and regulation, to the funding of research and development and timescales for the Brexit negotiations.
Mr Jackson said: "The European Union is a political entity constructed by politicians. We have come to a fork in the road and we had to make a decision about which way to go."
He said: "The process of leaving will take 12 to 15 months and we should leave in April 2019."