The new points-based immigration system will not be enough to ensure sufficient numbers of high-skilled workers come to Britain, while a hostile atmosphere will deter others, according to a report.
The Work Foundation, a not-for profit organisation, warned that Britain could lose out to other countries and face a shortage of "knowledge workers" in the future - those involved in the IT, healthcare, science and technology fields - unless the government acts.
The UK has been successful in attracting foreign involvement so far, with 167,000 high-skilled workers arriving since 2005, official figures show.
The bulk of these are Indian IT specialists, followed by workers from the United States, the Philippines, South Africa and Australia.
The UK employs the third-largest number of migrants with professional and technical skills, after the U.S. and Canada.
But an ageing population and an increasing demand for skilled workers elsewhere could result in a shortage.
"Politicians need to actively make the case for highly skilled migration," said report author Katerina Rüdiger.
"The new points-based system in the UK will not be enough on its own."
The lack of availability of so-called human capital - the skills and aptitudes of people - would deter foreign investment and result in falling competitiveness.
Human capital is among the most important factors influencing multinational companies when they decide to locate, said the report: "Towards a Global Labour Market?"
"Global firms need more global people - not just to fill shortages, but for the sake of enabling firms to innovate," it said.
It called for the entry criteria to be relaxed, but did not detail any further specific requirements.
Instead, the foundation called for the UK "to be seen as being among the most open and attractive places for highly skilled people to want to move".
"Talented people want career opportunities, the chance to expand knowledge by working with the brightest and best, good salaries, and the creation of diverse and exciting cities," it said.
The report went on to say that a climate of hostility towards immigration in general had the potential to harm the ability of firms to attract skilled, talented people from abroad.
