MILAN, Italy - Italian online fashion retailer Yoox said on Wednesday it may struggle to meet analyst expectations of an 18 percent rise in full-year revenue after its sales grew 15 percent in the first nine months.

The Bologna-based group posted sales of 366.3 million euros (286.08 million pounds) in the period, helped by the strong performance of its three shopping websites.

Italians' love affair with smartphones and tablets helped push domestic sales up 24 percent despite the country's stagnating economy.

However, the company said consensus forecasts for the full-year flagging overall sales at 537 million euros and earnings before interest, tax, depreciation and amortisation (EBITDA) at 53.5 million euros looked "a bit challenging".

"But we have never been better prepared to tackle the all-important Christmas campaign: many activities have been ... carefully planned all year long and the entire team is focussing their every effort on meeting our targets," Yoox said.

Nine-months EBITDA rose 26 percent to 27.1 million euros.

European sales performed well but the weakness of the Russian rouble and that of the Japanese yen hurt sales in those two countries.

Promotions following an unusually cold spring curbed sales growth in North America. Organisational issues as well as the decision to end an e-commerce partnership with denim brand Diesel in the United States from November 2013 also had an impact.

Yoox operates online shops for dozens of luxury brands ranging from Armani to Alexander McQueen, the latter as part of a joint venture with French luxury group Kering.

Revenue from Yoox's three websites accounts for nearly three quarters of the total and their growth pace is more than double that of the revenues generated at the partnerships with luxury brands, which have stalled.

But company founder Federico Marchetti told an analyst call that, after concentrating on the Kering joint-venture for two years, Yoox would return to seal new partnerships and pointed to the second half of next year.