He said: "It is vitally important that we have strict rules in place to protect the integrity of our benefits system.
"The British public are rightly concerned that migrants should contribute to this country and not be drawn here by the attractiveness of our benefits system. And we are taking action to ensure that that is the case.
"The roll-out of the new habitual residence test is the first in a series of measures to ensure that we have a fair system - one which provides support for genuine workers and jobseekers, but does not allow people to come to our country and take advantage.
"It is a crucial part of our long-term plan to secure Britain's economy."
Migrants are to be questioned about their English language skills and what efforts they have made to find work before they are able to claim income-related benefits, the Government has announced.
It said a "more robust" test is being rolled out at jobcentres across Wales, England and Scotland this week.
In order to pass a habitual residence test, migrants will have to answer more individually tailored questions, provide more detailed answers, and submit more evidence before they will be allowed to make a claim.
For the first time migrants will be quizzed about what efforts they have made to find work before coming to the UK and whether their English language skills will be a barrier to them finding employment.
A migrant boat presumed to be heading for Italy has capsized in western Greece, killing 12 onboard, authorities said today.
Fifteen others were rescued off the coast of Lefkada, an island in the Ionian Sea, and were taken to a hospital on the island for observation.
Coastguards are searching for more possible victims and survivors, the Merchant Marine Ministry said.
Ministry officials said the migrants were using a plastic boat which was about 25ft (8 metres) in length. It is not yet known where the boat began its journey.
This latest boat tragedy follows the deaths of at least 27 people in the Mediterranean sea last month - a week after more than 300 Africans lost their lives when their boat capsized near their destination of Lampedusa, Italy.