Global luxury giant Richemont said it was buying up a pioneering 10-year-old web-based women's fashion retailer, Net-a-Porter, founded by a former editor and valued at £350 million (€394 million).

The Swiss group already owns one-third of the business, which was created by Frenchwoman Natalie Massenet and employs 600 staff in London and New York.

But its wholehearted venture into internet fashion retailing would turn the website into one of the luxury goods company's hallmark "maisons", alongside standalone brands such as Cartier, Dunhill, IWC, Piaget and Van Cleef & Arpels.

Ms Massenet would remain as chief executive officer and will invest in a Richemont unit being created to own the online business, the Swiss group said in a statement.

"Richemont announces that it has made an offer... to acquire all of the shares in Net-a-Porter," the Swiss company said in a statement.

"The offer values the equity of Net-a-Porter at £350 million."

Richemont said that it had already received firm acceptances for its offer to buy outstanding shares in Net-a-Porter from owners of stock representing more than 80 per cent of the voting rights.

The total valuation given by Richemont, equivalent to €395 million, amounts to about three times the website's annual sales last year of about €135 million.

Net-a-Porter has adopted the lively style of a chic fashion magazine to sell collections from more than 300 well-known designers, selling to customers in more than 170 countries.

It offers some 300 brands including Jimmy Choo, Stella McCartney and Givenchy, delivering clothes and accessories from an €18 triple pack of socks up to a €16,600 handbag with a few clicks of a mouse.