Non-EU high earners' migration cap to be lifted
Non-European Union workers earning more than £150,000 a year are to be excluded from the government's immigration cap.
Scientists will also be given "a significant advantage" in coming to the UK as firms attempt to fill jobs where there are staff shortages.
Immigration minister Damian Green said the UK had to "attract the brightest and the best" to promote recovery.
Intra-company transfers have already been exempted from the cap after pressure from business.
The government has said it wants to cut the overall non-EU immigration limit from about 200,000 to "tens of thousands" by 2015.
This will be split into monthly allocations with a total of 4,200 available for the first month in April, with 1,500 each month after that - a total of 20,700.
'Made it clear'
Certain types of scientist will also be given priority, following concerns UK-based research would be harmed by the cap.
Mr Green said chemists, biochemists, physicists, geologists and research and development managers will all be among those given an advantage, while high earners would be exempt.
He added that the new rules will only apply to new applicants and not to those already in the UK, although those wanting to settle in the UK would have to be clear of any criminal convictions.
Mr Green said: "Britain needs to attract the brightest and the best to fill jobs gaps but this should never be at the expense of workers already here.
"We have worked closely with businesses while designing this system and made it clear employers should look first to people who are out of work and who are already in this country."
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.
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.
Firms will need to have already advertised the job in the UK and failed to find a suitable candidate.
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 will be introduced.
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.
Employers group, the CBI, welcomed what it said was the government's decision to "prioritise skilled workers" - saying it was vital if the UK was to remain an "attractive place to invest".
Adam Marshall, director of policy at the British Chambers of Commerce, said: "Business said loud and clear that any new immigration rules must still let companies access the right talent, at the right time, when domestic workers are unable to fill skills gaps.
"The new rules show that, after a period of great uncertainty, the government is listening harder to business concerns."
Meanwhile, Labour accused the government of leaking the announcement to the media, rather than announcing it in Parliament as they are supposed to do.
Shadow Home Office minister Gerry Sutcliffe said the Home Office had become a "serial offender" in briefing the media in advance of important announcements.
The Russell Group of leading universities welcomed the changes for scientists and academics.
"Higher education is one of our most successful export industries. If we are to maintain our place in the premier league of global higher education, it is crucial that our visa system continues to support the efforts of our leading universities to attract the very best academics from around the world," said director general, Wendy Piatt.