That would equate to around $15.4 million of Kathmandu's $384 million total sales figure in its last financial year.
The company estimates that 20 per cent of its online sales are likely to come from mobile devices.
Chief executive Peter Halkett said the new mobile site reflected Kathmandu's continuing investment in its online business.
"We know that there is a big move away from desktops towards the use of smartphones and mobile devices for shopping and pre-shopping and if we can make it easier to search and to shop that is likely to deliver increased sales," Halkett said.
He said the 4 per cent of Kathmandu's total sales currently generated online was "only the tip of the iceberg".
"We want to give customers the best platform to shop online," Halkett said.
Market research firm Nielsen's latest online retail report found 45 per cent of the 1.8 million New Zealand online shoppers used mobile devices to browse for goods and services on the internet, while 26 per cent had made an online purchase on their device.
Of the shoppers, 288,000 used smartphones and 239,000 used a tablet computer, the report said.
Almost 6 per cent of total New Zealand retail sales were made online last year, up from 5.1 per cent in 2011, according to research by PwC and Frost & Sullivan, which also found the average Kiwi spent $1659 online in 2012.
Shares in Kathmandu - which have been the second-best performing on the NZX-50 this year, gaining more than 90 per cent - were down 3c at $3.52 in early trading.
The company reported a 26.6 per cent lift in net profit to $44.2 million in the 12 months to July 31.