* Symbian sales to continue as long as profitable
* Telco venture NSN's Motorola deal delayed by China review
* Nokia shares up 2.3 pct, rally from recent lows
(Adds comments, updates shares, wraps separate)
By Tarmo Virki, European technology correspondent
HELSINKI, March 9 Nokia Oyj NOK1V.HE reinforced its commitment to its legacy Symbian platform on Wednesday, easing concerns it could face an awkward gap until the launch of new products under its planned Microsoft (MSFT.O) venture.
The comments on Symbian from a Nokia executive on Wednesday helped lift the Finnish mobile phone maker's shares above recent lows to trade up 2.3 percent at 6.20 euros by 1255 GMT. The STOXX Europe 600 technology index .SX8P was up 0.4 percent.
The comments also offset an admission from Nokia's telecom gear venture with Siemens (SIEGn.DE), Nokia Siemens Networks (NSN) [NOKI.UL], that its $1.2 billion acquisition of Motorola's network unit would be delayed further due to an extended review by Chinese authorities.
Symbian is due to be replaced by Microsoft's Windows Phone over the coming two years under a plan announced in February, raising concerns over what Nokia would do with its existing product lines in the meantime. [ID:nLDE71E1KZ]
"We will of course utilise the long tail of Symbian as long as it gives us a profitable margin," Nokia Chief Financial Officer Timo Ihamuotila told a technology conference organised by Switzerland's UBS. He noted a final contract with Microsoft was yet to be signed.
Ihamuotila said the so-called long tail in phone sales, when volumes are lower than after launch, has often lasted longer than expected in the mobile industry.
Industry watchers said it was important for Nokia to manage the transition to new Microsoft-based products.
"Symbian faces similar challenges to Mark Twain, whose death was famously announced prematurely," said Ben Wood, head of research at British consultancy CCS Insight.
"Nokia must come out with a strong message that its legacy smartphone platform is alive and well as sales of Symbian devices are going to be critical for the next 18 months," Wood said.
For NSN the delayed Motorola (MSI.N) deal is intended to strengthen it against its key Chinese rivals and make it the second-largest mobile telecom gear maker ahead of China's Huawei [HWT.UL].
NSN said on Wednesday China's antitrust authority was undertaking an extended review of the deal likely to take another 60 days. It would therefore not be completed in the first quarter as had been planned.
NSN said it remained committed to the acquisition but would provide no further guidance on when it was likely to be completed.
NSN had originally hoped to close the deal by the end of 2010, but had already delayed it to the first quarter pending approval from China.
Analysts have said the delay is holding up talks by NSN's parents with private equity firms over the sale of a minority stake in the venture.
Nokia and Siemens said last August they had been approached by private equity firms interested in buying a stake in NSN.
Siemens has said taking the venture public was possible in the medium term. (Additional reporting by Jussi Rosendahl and Sinead Carew in New York; Editing by Hans Peters and David Holmes)