Italian online fashion retailer Yoox-Net-A-Porter said on Wednesday revenues would grow further this year and core earning margins would improve on last year as it posted a 12 per cent rise in reported third quarter sales.

Revenue was up to 435 million euros ($476 million), just below an average analyst estimate by Thomson Reuters of 438 million euros. Sales rose 17 percent at constant exchange rates.

Sales at YNAP's off-season business, which includes websites Yoox and The Outnet, rose 16.8 percent while in the same nine months its higher-end in-season business posted a 7.2 percent rise in sales.

The group processed 5.9 million orders in the first nine months of the year, up from the 5 million in January-September last year.

But the average order value was 351 euros, slightly below the 354 euros in the same period last year. (Reporting by Giulia Segreti)