"Today a number of people have arrived in the UK as part of the Vulnerable Persons Resettlement scheme," said a Home Office statement.
The government would not give details of how many refugees had arrived, or where in Britain they would be resettled.
Under the expanded scheme, the new arrivals will receive housing, access to medical care and education and will be granted five years' humanitarian protection.
After that period they will be able to apply to stay in Britain.
Prime Minister David Cameron announced earlier this month that Britain would take 20,000 refugees from camps in Jordan, Lebanon and Turkey over the next five years after coming under pressure to do more to ease the crisis sweeping Europe.
"This provides refugees with a more direct and safe route to the UK, rather than risking the hazardous journey to Europe," Cameron said.
Britain had accepted 216 Syrian refugees under the scheme before this month's announcement and has granted asylum to almost 5,000 since the Syrian conflict broke out in 2011 -- far fewer than countries such as France, Germany and Sweden.
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Vulnerable refugees such as orphans will be given priority, according to the prime minister, who had an apparent change of heart after the image of a dead Syrian toddler washed up on a Turkish beach sparked a groundswell of public sympathy.
European Union ministers on Tuesday pushed through a deal to relocate 120,000 refugees, but faced fierce opposition from central and eastern states.
Britain is exempt from EU asylum and migration policy and Cameron had already made it clear that the country will not be involved in any quota system.
Cameron visited Syrian refugee camps in Lebanon and Jordan last week, pledging an extra 100 million pounds ($153 million, 137 million euros) in aid, which he said would help stem the migration crisis.
He said in Beirut that Britain was doubling its support for Lebanon's schools to 20 million pounds a year for the next three years to help Syrian refugee children as well as Lebanese.
Boosting aid to regional states hosting refugees was key to tackling the crisis that has seen tens of thousands of asylum-seekers flood into Europe, Cameron said, reiterating his argument against charges that London was not doing enough.
The surprise visits, which included talks with Lebanon's prime minister and the king of Jordan, came as Cameron appointed a minister to oversee the resettlement of the 20,000 refugees.
In total, more than four million Syrians have fled abroad from a brutal conflict that has left more than 240,000 people dead.