The European Union has criticised the Conservative plan to block EU citizens from receiving UK benefits.
Employment Commissioner Laszlo Andor said Britain risked being seen as a "nasty country" because of the plan, which would mean a person needs to be resident in the UK for three months before they were entitled to benefits.
From 1st January people from Bulgaria and Romania will have full workers rights in the whole EU, prompting fears from some that the UK jobs market will struggle to accommodate them.
David Cameron, writing in The Financial Times, said that one million people from central and eastern Europe have settled in the UK since a number of new countries joined in 2004.
The Prime Minister has proposed a range of cuts, including no immediate access to housing benefit, Jobseeker's Allowance removal if the EU citizen has little "genuine" chance of getting work after six months, a new "minimum earnings threshold" so that low-paid workers will not get benefits, forced removal of homeless EU citizens, and increased fines for employers paying less than the minimum wage.
Cameron welcomed the free and open market the EU provides but did not recognise that the free movement of labour is part of this market.
Laszlo Andor warned that demonising these new workers could create "hysteria" and said that British people were not getting the "full truth" about how immigration helped countries.
He also called the Prime Minister's article a "huge over-reaction" to the issue.
The EU has published its own study on the benefits of migration, finding that migrants were more likely to be employed than local people
It also "found little evidence" that people were moving to get benefits, saying that "immigrants are not more intensive users of welfare than nationals".
Romanian and Bulgarian politicians fear that higher wages elsewhere in the EU could lead to a brain drain, meaning countries like the UK benefit from attracting those with high skills while their countries of origin are left behind.