Online fashion portal Asos is to increase investment into its warehousing as it aims to increase sales capacity to £2.5bn a year, more than £1bn higher than previous guidance.

The firm, which caters to fashion conscious twenty somethings, posted a retail sales rise of 26 per cent to £136.7m as UK sales increased 21 per cent to £48.4m in the two months to February 28.

International sales now account for 65 per cent of total sales – up 53 per cent for the same time last year.

Chief executive Nick Robertson commented: “It has been an exceptionally busy period of activity at Asos, with continued growth and accelerated investment.

“The group delivered strong sales and margin growth over the first six months of the year and we are now confident of achieving £1bn of sales in 2013/14.

“We ended the period with 8.2 million active customers, a 36% increase year on year.”

David Alexander, Retail Analyst at Conlumino said Asos is putting the wheels in motion for even more growth.

“Investments in technology are not just benefitting Asos‘s customers, they are also helping the buying and trading teams.

“The company uses real-time data to collect information from blogs, social media, competitor websites and press mentions on a daily basis, which then assists buyers and merchandisers with their ranging and pricing decisions, helping to ensure that Asos‘s product lines are trend-lend and up to the minute.”

Shares in Asos have almost doubled in the last year, giving it a market value of £5.3bn, only £2.3bn less than 130 year-old Marks & Spencer, Britain‘s biggest clothing retailer.