Tens of thousands of children who live abroad but receive benefits claimed by immigrant families in Britain are costing British taxpayers more than £1m a week, campaigners claim.
The research by Migration Watch UK comes after the Government admitted just under 30,000 families are claiming benefits and tax credit for 50,000 children who live outside the UK but within the European Union (EU), as well as Iceland and Norway.
It costs the UK taxpayer £55m a year to fund this system, which is only replicated in four other EU countries - 22 nations require the child to be resident in order to qualify.
Migration Watch UK chairman Sir Andrew Green said: "It is absurd that child benefit is paid to children who do not even live in the UK.
"At a time that UK taxpayers are being asked to tighten their belts, the Government is paying out over £1m per week to support children in other countries where costs are, in any case, often much lower.
"The majority of EU countries have the good sense to ensure that the child in question must be resident in that country in order to qualify and it is about time the UK did the same."
Poland is home to the highest number of children in the region who are receiving benefits claimed in the UK, with more than half the total, 25,659, receiving welfare.
Child benefit in the UK is worth £81.20 per month for the first child and £53.60 for the second and subsequent children. This is roughly four times higher than Polish rates.
Migration Watch calculated that child benefits paid to 40,171 children living overseas costs the UK £36.6m per year and child tax credit costs £18.6m per year.
The UK, Czech Republic, Germany, Latvia and the Netherlands allow child benefit to be paid for children who live elsewhere in the EU.
The original figures were disclosed by Treasury minister Sajid Javid in a written answer to Keith Vaz, chairman of the Home Affairs Select Committee.
The data will add to concerns about the impact of an expected wave of immigration from Romania and Bulgaria when temporary controls lapse at the end of the year.
Last week, a HMRC spokeswoman said EU rules allow EEA nationals to claim child benefit if they meet the relevant conditions and pay compulsory national insurance contributions.