More than a million people across Europe, including 180,000 in the UK, have signed a petition opposing trade deals between the European Union and North America.
The World Development Movement (WDM) said the Transatlantic Trade and Investment Partnership (TTIP) had provoked strong opposition, which critics claim could lead to health services being privatised.
Unions and campaign groups are opposed to the deal, which the Government maintains will boost business in the UK, create jobs and fuel the economy.
Nick Dearden, director of the WDM, said: "The European Commission is desperately fighting to prevent a critical debate from taking place about these trade deals with North America.
"With TTIP threatening labour rights, environmental standards and vital public services like the NHS, it's not surprising that more than a million people have voiced their opposition to it in such a short space of time."
Trade Minister Lord Livingston said: "Pressure groups are misleading people into believing that TTIP will lower standards and put the NHS at risk. This is simply not true, as the EU, the US and the UK Government have all made clear.
"TTIP will, however, make it easier for small businesses to export and will mean more choice for consumers and lower prices in the shops."
It’s wonderful that we have a new European Commission coming in, especially one that is avowedly committed to greater transparency about the revolving door between EU politics and big business.