Sporting goods company Nike is taking measures to enforce water usage guidelines at factories in its global textile supply chain.

The US firm has introduced a traffic light system to monitor how well each its suppliers are performing at minimising water usage, but vowed to help those factories tipping the scales.

John Frazier, head of Nike's restricted substances list and green chemistry programme said: "Water is becoming more and more of an issue, and an accelerated issue. We have a lot of conversations about CO2 and global warming, which are both appropriate, but we also need to start having conversations about water, especially in the apparel industry."

Speaking at a conference organised by ethical textiles group RITE, Frazier noted that 1.1bn people across the globe have no access to drinking water, with 2.6bn without access to proper sanitation.

He pointed out that parts of Asia and Northern Africa - major textile producing regions - were already suffering from water scarcity.

Including the complete production cycle, Frazier admitted that when you consider it takes 2,650 litres of water for a single T-shirt and around 10,000 litres for a pair of jeans, that the "numbers are gigantic".

Nike has estimated that the apparel industry uses around 40bn gallons of water per year in the production chain, and Nike's programme is looking to address this by regulating water usage at 400 of its suppliers, and assessing their levels by way of its traffic light system.

"If we rate them as red, they have to do something to improve. Our role is not to walk away from them," Fazier said. "Because if we walk away they're not going to improve. We will give them timelines and we'll check that there's been progress towards these goals but our intention is to improve them rather than walk away. Having said this, we have had to walk away from some because they just wouldn't do anything."

This year's RITE Group Conference in was held in Westminster, London.

By Joe Ayling, news editor.