The committee said the new system was working well
The new points-based immigration system for bringing in skilled workers from outside the EU needs strengthening, a group of economic advisers has said.
Earning thresholds should be raised and jobs advertised in the UK for longer, said the Migration Advisory Committee.
Also, arrangements for transfers within firms should be strengthened and penalties for abusing rules increased.
The Home Office said the government would carefully consider the "robust and thorough" report.
The report concerned itself with "tier two" of the points-based system, which was introduced last year.
This refers to skilled people who have a job offer - often those who work in sectors such as health, management, science and finance.
Workers gain points if they would fill gaps in the labour market - the committee advises ministers on which skills the economy needs.
Some 50,000 such workers are expected to arrive in the UK this year.
Nearly half of them come from India, but also significant numbers from the US and Australia.
The committee's chairman, Professor David Metcalf, said tier two was "working well".
"But our advice to the government is that the labour market could be helped by requiring higher standards from skilled workers outside of the EU before we allow them to work in the UK.
"We believe that selective immigration that favours skilled workers, as the PBS [points-based system] does, is vital to ensure that the UK continues to be a good place to do business or invest.
"However, it is important that British workers are not displaced. We have therefore made a number of recommendations which will help to avoid undercutting and any disincentives to raise the skills of UK workers."
• Specific qualfications should be seen as equivalent to NVQ level 3, or bachelors or masters degree level
• Workers should earn £20,000 and those without qualifications at least £32,000
• There should be a new category for key public workers
• Adverts for vacancies should be increased to four weeks.
Home Office Minister Lord West said the points-based system had "proven itself to be a powerful and flexible tool in meeting the needs of the British workforce and business in these changing economic times.
"From the outset we demonstrated that flexibility by putting a stop to low skilled labour entering the UK from outside Europe.
"In light of the economic downturn we have taken further steps to be more selective of migrants that come to the UK and to give resident workers every opportunity to fill vacancies.
"The MAC has delivered a robust and thorough report and the government will consider it carefully over the coming weeks."
But shadow immigration minister Damian Green said there was "one big gap" in the system.
"There is no overall limit on how many permits can be issued in any one year. This is why the public has a lack of confidence in the immigration system, which people regard as being out of control," he said.
"This is why a Conservative government would introduce an annual limit, so that Britain can continue to attract those who will help our economy without putting too much pressure on our essential public services."