UPDATE 2-Option says H2 growth uncertain, shares tumble

* H1 net loss 20.5 mln eur vs 16.8 mln last time

* Says new products won't create proper sales until 2011

* Stock down 18 percent, hits 11-week low

(Adds share price)

BRUSSELS, Aug 31 (Reuters) - Belgium's Option NV (OPIN.BR) (OPNVY.PK), Europe's only maker of wireless modems, said it was not sure it could grow in the second half of the year as it felt the pressure of cheaper imports from China.

Its shares fell by as much as 18 percent, making the company the biggest faller on the Euronext Brussels exchange and taking its share price to an 11-week low.

The company, whose modems can access the Internet over the mobile phone network, said on Tuesday growth in the second half of the year would be uncertain unless it could accelerate the roll-out of new products.

Its net loss widened to 20.5 million euros ($26.1 million) in the first six months of the year from 16.8 million in the same period in 2009.

Shares in Option have fallen from a peak of over 16 euros in 2006 to less than 1 euro as it suffered fierce competition from Chinese rivals Huawei Technologies [HWT.UL] and ZTE (0763.HK) (000063.SZ).

European Union trade regulators opened an investigation in June after a complaint by Option that Chinese-made wireless modems were being sold in the EU for less than they cost to produce, which is illegal under international trade laws. [ID:nLDE65T22C] (Reporting by Ben Deighton; Editing by Sharon Lindores and David Holmes) ($1=.7861 euro)