NET-A-PORTER has received a bid approach from Richemont, the Swiss luxury-goods group, that would value the online fashion boutique at about £350m.

Richemont, which controls a 29% stake in Net-a-Porter, is understood to be in detailed discussions to buy out the shares in the business that it does not already own.

If a deal is agreed, Natalie Massenet, 44, the former fashion journalist who founded Net-a-Porter in 2000, is expected to sell at least part of her 18.2% stake.

Net-A-Porter is one of the fastest-growing private companies in Britain. In the 12 months to January 31, 2009, it defied the credit crunch and the recession to notch up a 234% rise in pre-tax profits to £10.1m on sales of £81.5m — up 47.8% on the previous year.

Net-a-Porter and Richemont, which owns Cartier and other luxury brands such as Alfred Dunhill, both refused to comment this weekend.