TaxPayers' Alliance chief executive Jonathan Isaby said: "This is a disgraceful abuse of taxpayers' money.
"When cash is scarce and budgets are tight, politicians should not be wasting nearly £10 million of our cash on political propaganda.
"The country is having an important debate about its relationship with the EU and it is essential that it is held on a level playing field.
"When provisions are already in place for each official campaign to receive equal amounts to help make their case to voters, this move will only serve to unfairly skew the debate.
"This is not 'government money', it is all taxpayers' money and it is deplorable that ministers see fit to use it to try and instruct us how to vote."