Rogue employers who give jobs to illegal immigrants will be hit with the "full force" of the government machine ministers have warned.
Immigration minister James Brokenshire said the Government was determined to act against businesses which were denying work to British nationals and driving down wages.
His comments came as The Times reported that immigration officers were preparing to mount a wave of raids this autumn targeting building sites, care homes and cleaning contractors.
"Rogue employers who give jobs to illegal migrants are denying work to UK citizens and legal migrants and helping drive down wages," Mr Brokenshire said.
"Experience tells us that employers who are prepared to cheat employment rules are also likely to breach health and safety rules and pay insufficient tax.
"That's why our new approach will be to use the full force of government machinery to hit them from all angles and take away the unfair advantage enjoyed by those who employ illegal migrants."
His intervention came after Foreign Secretary Philip Hammond said the huge influx of migrants coming from Africa was threatening to undermine social cohesion and living standards across Europe.
Mr Hammond said the continent could not absorb "millions" of Africans and called for the overhaul of EU laws to ensure those coming simply to find a better way of life could be returned to their own countries.
He said in many cases, migrants knew they once they managed to reach Europe for there to be little chance of them ever being forced to leave.
His comments were condemned as "mean-spirited" and "shameful" by Amnesty International while Labour said the Foreign Secretary was guilty of "scaremongering".
Speaking during a visit to Singapore, Mr Hammond said the gap in living standards between the two continents meant there would always be an "economic motivation" for Africans to try to make it to the EU.
"As long as the Europe Union's laws are the way they are, many of them will only have to set foot in Europe to be pretty confident that they will never be returned to their country of origin," he told BBC News.
"Now, that is not a sustainable situation because Europe can't protect itself and preserve its standard of living and social structure, if it has to absorb millions of migrants from Africa."
Mr Hammond said ensuring migrants could be returned to their country of origin was also the key to resolving the "crisis" at Calais, where hundreds are gathered in the hope of being able to make it across the Channel to Britain.
"So long as there are large numbers of pretty desperate migrants marauding around the area there will always be a threat to the tunnel's security," he said.
Steve Symonds of Amnesty International UK denounced his comments, saying the Government had a duty to protect people fleeing conflicts and brutal regimes.
"With countries like Lebanon, Ethiopia and Chad hosting far more refugees than the UK and other European countries, the Foreign Secretary's mean-spirited response is shameful," he said.