Firms should look to hire unemployed Britons as the Government's annual immigration cap for workers from outside the EU comes into force today, Immigration Minister Damian Green said.
Just 20,700 skilled workers from outside the EU will be allowed to come to the UK this year, with 4,200 places available this month, followed by 1,500 in each month after that.
The move is part of Government efforts to meet its pledge to cut net migration from 200,000 to the tens of thousands by 2015.
Mr Green said: "We have made clear that as the recovery continues, we need employers to look first to people who are out of work and who are already in this country.
"We are overhauling all routes of entry to tackle abuses, make the system more effective and bring net migration back down to the tens of thousands."
A further 1,000 exceptional talent visas will available for the "brightest and the best" contributors to science and the arts, he said.
"We are sending out a clear message - the UK remains open for business and we want those who have the most to offer to come and settle here."
Intra-company transfers (ICTs), used by firms to bring their own people into the UK for more than a year to do specific jobs, will be excluded from the cap, but a minimum salary of £40,000 is also being introduced, the Home Office said.
But firms will still be able to bring non-EU workers into the UK on ICTs for less than 12 months as long as they earn £24,000.
The Government will also bring in a 12-month "cooling-off" period before allowing any workers who leave the UK to return on another ICT.
Each application for a certificate of sponsorship - which firms will need to bring skilled migrants into the UK - will be ranked with the most points awarded for jobs on the shortage occupation list, those requiring a PhD and high earners.
If any month is oversubscribed, those with the most points will be granted permission to come to the UK, the Home Office said.
If demand exceeds the allocation by fewer than 100 in any month, those places will be taken from the following month. Any unused places will also be rolled over to the following month.
All skilled workers from outside the EU will need a graduate-level job, as defined by the Migration Advisory Committee's list, speak an intermediate level of English, and earn at least £20,000.
The measures are designed to stop non-EU migrants coming to the UK as skilled workers but working in fast food outlets, beauty salons and estate agents.
Firms will need to have already advertised the job in the UK and failed to find a suitable candidate.