Jose Luis Duran, chief executive of Carrefour, said the retail sector was facing some of its most significant challenges in a generation, as he kicked off the industry’s annual conference in Barcelona.

Mr Duran told over 1,000 delegates that the outlook was tough for the global players as consumers digested the fall-out of the credit crunch and rising commodity prices across the world.

“We are facing the most significant challenges in a generation,” said Mr Duran. “We are facing rising energy costs and inflation in selling prices.”

He also said that retailers’ costs were “growing faster than prices”, adding that this was a structural rather than cyclical trend -- although he stressed that Carrefour was in good shape and was not changing any profit guidance.

Paul Charron, chairman emeritus of Liz Claiborne, the US fashion chain, was equally downbeat, arguing that the US economy was in no shape to pull the rest of the world through a downturn.

“It is a stretch to think that the US consumer will bring back to some sort of normality. The economic problems will continue to be played out. Consumer spending will be buoyant again but it will take some time longer,” he told the conference.

The remarks came on the heels of an admission by Anders Dahlvig, president and chief executive of Swedish chain Ikea that it is suffering like-for-like sales declines in some of its markets and has warned that the pattern could spread across Europe as falling house prices hit flat-pack furniture.

“It is especially when the housing market is down [that] it certainly affects our type of business,” Mr Dahlvig told the Financial Times.

“We see it not only in markets [such as] the US or UK… but we see it in Spain, we see it in Italy, we see it in Germany… Of course this will probably spill over to other European markets as well; I can see that in the coming months.”

The bearish comments helped push the shares of European retailers lower. Carrefour shares fell 3.9 per cent to €47.52. Casino Guichard-Perrachon, the biggest supermarket owner in Paris, slid 2.4 per cent to €77.51. Metro AG, Germany’s largest retailer, dropped 1.4 per cent to €49.99.

Mr Duran, who is unifying dozens of sub-brands dotted around the world under the Carrefour name in an effort to cut costs and increase own-label sales, said he would take a decision on rebranding the Champion French chain -- which is 1,000 stores strong - in the next eight weeks. He also said that Carrefour would press on with its property IPO in 2009, having decided this year to do a private placement of €1.5bn becasue of the difficult equity markets.