An emergency brake on benefits is "highly unlikely" to stop EU migrants heading to Britain it was claimed after records showed just "quite low" numbers claimed tax credits.
Some 84,000 EU migrant households who arrived in the UK or had been issued a National Insurance number during the previous four years received the benefit 2013/14, according to HM Revenue and Customs.
Figures released under Freedom of Information laws showed that 50,000 were claims from couples and 34,000 were single claims.
Proposals for reforming Britain's relationship with Brussels include an emergency brake to restrict benefits for migrant workers with benefits phased in over the four-year period.
Jonathan Portes, principal research fellow at the National Institute of Economic and Social Research, said: "This new data shows that the Prime Minister's claim that 40% of recently arrived European migrants were dependent on benefits was at best selective and misleading.
"Given that well over a million European migrants registered for National Insurance numbers over the period in question (and far more since) this suggests that claim rates among newly arrived migrants are, as researchers have always argued, quite low.
"Once again this suggests that the PM's focus on this issue is misguided - the "emergency brake" will have only a modest impact on benefit receipt, and is highly unlikely to have a significant impact on migration flows.
"This latest data still leaves some important questions unanswered. In particular, the Government is still refusing to tell us - for obvious political reasons - how many recent European migrants are recorded as being active in the UK labour market."
The emergency brake proposals and plans for a "red card" allowing parliaments to block laws from Brussels have been further ridiculed by Eurosceptic Tories, with claims they are a "desperate attempt to put lipstick on a pig".
Prime Minister David Cameron has been meeting key players from the EU in London, holding talks with European Council president Donald Tusk, Slovak PM Robert Fico, Greek PM Alexis Tsipras, Swedish PM Stefan Lofven and Belgian PM Charles Michel, in the margins of the Syria donors' conference in London.
Former Home Secretary Alan Johnson, the leader of Labour's campaign to remain in the EU, said the emergency brake would have no impact on immigration as in-work benefits were not a factor in drawing people to the UK.
Asked whether Mr Cameron believes the proposed "emergency brake" will cut immigration, a Downing Street spokesman said that migrant families were currently able to claim an average of £6,000 a year in tax credits and some 10,000 were claiming £10,000 or more.
Mr Tusk's reform package "acknowledges what the Prime Minister has been saying for a long time, that the benefits system is an unnatural draw for EU nationals", said the spokesman. "I think common sense would tell us that reducing the financial incentive will reduce that pull factor."
In the Commons, Eurosceptics lined up to criticise the proposed deal, with European Scrutiny Committee chairman Sir Bill Cash telling MPs: "These negotiations, when you cut through all the appearances, are a sham. "