George Osborne has triggered a backlash from charities after he urged companies to defend the economy against their “anti-business views” and those of pressure groups and trade unions.

The chancellor called on business leaders to raise their heads “above the parapet” and fight back against charities and others who he said were making arguments against the free market and standing in the way of economic prosperity.

Osborne told the annual convention of the Institute of Directors in London: “You have to get out there and put the business argument, because there are plenty of pressure groups, plenty of trade unions and plenty of charities and the like, that will put the counter view.

“It is, I know, a difficult decision sometimes to put your head above the parapet, but that is the only way we are going to win this argument for an enterprising, business, low-tax economy that delivers prosperity for the people and generations to come.

“There is a big argument in our country … about our future, about whether we are a country that is for business, for enterprise, for the free market.”

Osborne did not name any of the charities that had antagonised him, but his remarks are the latest in a string of comments by senior Conservatives suggesting they believe charities have got too political and leftwing.

Some MPs reacted furiously to a campaign poster by Oxfam released in June that described “a perfect storm” unleashed by zero-hours contracts, high prices, benefit cuts and unemployment. Brooks Newmark, the former civil society minister, last month urged charities to “stick to their knitting”.

Oxfam, which runs a large trading arm, rejected the idea that charities were in any way anti-business. Nick Bryer, its head of UK campaigns and policy, said the charity agreed with the chancellor about the importance of enterprise. “It is vital to tackling poverty around the world, which is why we help poor people set up their own businesses and access markets,” he said. “We don’t recognise the divide he draws between the concerns of businesses and charities.”

Sir Stuart Etherington, the chief executive of the National Council for Voluntary Organisations, said people “should be celebrating not denigrating the relationship between business and charities”.

He said: “The days when charities and businesses were enemies are long gone. Charities will always speak up for the people and causes they work for, but many are also working with businesses to find solutions to society’s problems together.”

The chancellor has been the target of criticism by many charities over the effect of government cuts, most recently by the Child Poverty Action Group, Gingerbread and other groups when he announced a further two-year freeze on working age benefits if the Conservatives win power next year. Many feel the negativity of some Tories towards charities has its roots in the fact that some, such as those who provide food banks, have played a high-profile role in highlighting the effects of welfare cuts.

Osborne’s broader suggestion that businesses know better than charities how to bring about prosperity was strongly questioned by John Sauven, the executive director of Greenpeace. “George Osborne appears to lack a sophisticated understanding of what brings about prosperity and happiness in societies,” he said. “Most league tables show countries that protect the environment and have progressive social policies have more fulfilled, satisfied populations. It’s not anti-capitalist to say clean water, clean air and sustainable growth are good for everyone.”

Labour said Osborne’s remarks showed that the Conservatives had forgotten David Cameron’s “big society” rhetoric. Lisa Nandy, the shadow minister for civil society, said Osborne made clear he thinks many trade unions and charities are the enemies of prosperity.

“It follows a long campaign of words and actions from this government that amount to a stunning attack on charities, from clamping down on the right to use judicial review to the introduction of the lobbying act,” she said. “It’s a far cry from David Cameron’s big society.”

Frances O’Grady, the TUC general secretary, said many of Britain’s most successful companies – such as carmakers – depended on the labour and skills of trade unionists just as much as their managers. “He has let down his guard to show how much he agrees with Margaret Thatcher’s ‘enemy within’ rhetoric,” she said.