The Confederation of British Industry is "blindly backing" EU membership without any criticism or thought, according to a Conservative MEP.
The CBI, one of the UK's biggest business groups, recently warned Prime Minister David Cameron that the country's economic success depends on the UK's full membership of the EU.
"The EU is our biggest export market and remains fundamental to our economic future," said John Cridland, director general of the CBI.
"Our membership supports jobs, drives growth and boosts our international competitiveness."
But David Campbell Bannerman, who represents the Eastern Region of the UK in the European Parliament, told IBTimes UK that the CBI "isn't doing any serious thinking".
"It's just maintaining a position where EU membership at all costs is benign for the UK," said the former deputy leader of Ukip.
He added: "What [the CBI] really needs to do is look at all the options outside of the European Union in more seriousness."
Campbell Bannerman said the UK should adopt a so called "EEA-lite" position, where Britain is out of the EU with a free-trade deal.
The arrangement, Campbell Bannerman explained, would be mid-way between the bilateral treaties that cover Switzerland's relationship with the EU and the European Economic Area (EEA) agreement covering the relationship between the three European Free Trade Association (EFTA) countries (Norway, Iceland and Lichtenstein) and the 28-member EU.
"The point about EEA-lite is that it could deliver a lot of what the CBI spends all of its time calling for, including massive cuts in red tape, better trade deals, more competitiveness in the economy – it could do all of these things."
He added: "The CBI shouldn't be blindly backing EU membership without any criticism or thought. I don't think it's doing its job effectively."
Campbell Bannerman also rejected the idea that all UK businesses would still have to abide by the EU's employment rules in order to trade with it – even if Britain left the economic and political union.
"EEA-lite proposes that the UK leaves the EU single market and re-establishes the British single market," he said.
"The point of doing that is staggeringly only 8% of the UK economy is trade with the EU, but the other 92% has to apply all of the laws, all of the regulations and directives and red tape.
"All of that, including the Working-Time Directive or the Temporary Agency Work Directive, is imposed on business when frankly there's no need to do so if you weren't in the single market.
"Obviously for the 8% of the economy that is trade with the EU you would have to follow those laws."
But a CBI spokesperson said the business body speaks on behalf of firms of all sizes, who employ nearly seven million people.
"In a survey last year, 78% of our members said they favour staying in the EU," the spokesperson said.
"Firms want what is best for jobs and growth, and there is genuine concern that an exit would hit business investment and access to the world's largest trading bloc.
"We will continue to press the case for the UK remaining in a reformed EU, signing more trade deals and boosting the single market."
The comments come after the former Prime Minister of Luxembourg Jean-Claude Juncker was elected as the President of the European Commission, the executive body of the EU.
The move was a blow to Cameron after the Conservative opposed the appointment, arguing that Junker favoured an "ever closer union" of the EU.
But the prime minister has since telephoned the new President of the EC elect to congratulate him and reassured the electorate that he can still "do business" with the senior European politician.