Labour also upped its rhetoric, suggesting it now wanted treaty changes to curb the free movement of people chasing jobs.
Viviane Reding, Vice President of the European Commission, accused David Cameron of peddling "populist myths" about EU migration, saying it was "simply not true" that there was an "invasion of foreigners", who were stealing jobs and draining welfare and health resources.
Ms Reding said: "I am mostly frustrated about the political leaders because what is leadership if you just try with populistic movements and populistic speech to gain votes? You are destroying the future of your people."
Her comments came after Donald Tusk, the Polish premier, protested about Mr Cameron's wanting to change a system under which EU migrants can claim UK child benefit for offspring living in their home country.
He also angered Laszlo Andor, the European employment commissioner, who warned Britain risked being seen as "nasty".
Tory backbencher Mark Reckless hit back, claiming the measures taken by the Coalition had been quite moderate. "It's these European politicians who seem to have been stoking this thing up," he declared.
He added: "People in this country get social security benefit but they spend it here. But very often people coming from Poland - and perhaps now from Romania and Bulgaria - are sending money home. It's quite wrong that if a child is being schooled in Poland and with family there that they should be paid child benefit by the taxpayers of this country."
Meantime, Chuka Umunna, the Shadow Business Secretary, strengthened Labour's position on migration, saying a Miliband government could seek new restrictions on the movement of people within the European Union.