UPDATE 1-Q3 net profit at Thailand's AIS up 42 pct
* Q3 net profit 8.79 bln baht vs forecast 8.7 bln
* Non-voice revenue up 32 pct, voice revenue up 6.2 pct
* Keeps 2012 service revenue target of 8-10 pct
* Shares down on concerns about 3G auction probe
BANGKOK, Nov 7 (Reuters) - Advanced Info Service Pcl (AIS) , Thailand's top mobile phone operator, matched expectations with a 42 percent rise in quarterly net profit on Wednesday as the popularity of smartphones and social networks boosted demand for data services.
AIS, Southeast Asia's biggest wireless firm by market value, is expected to benefit from strong domestic consumption in the fast-growing Southeast Asian country as affordable mobile handsets and low tariffs stimulate demand for mobile usage, analysts said.
The market leader maintained its service revenue growth target of 8-10 percent after posting an 11 percent rise in the first nine months, it said in a statement.
AIS, 21 percent owned by Singapore Telecommunications Ltd , posted a net profit of 8.79 billion baht ($286 million) for the July-September period, up from 6.17 billion a year earlier. The result was in line with the average forecast of 8.7 billion baht from 11 analysts polled by Reuters.
The country's second-most valuable company has about 50 percent of the cellular market in Thailand, ahead of Total Access Communication's roughly 30 percent.
Last month, Total reported a 6.2 percent fall in net profit due to rising regulatory fee and higher network expenses.
AIS's third-quarter total revenue rose 8.7 percent, led by a 32 percent increase of non-voice services and 6.2 percent rise in voice services.
At the end of September, AIS has 35 million subscribers after adding a net 515,500 in July-September.
Shares in AIS, valued at $18.6 billion, have underperformed the market in the past month due to concerns about an investigation into a 3G spectrum auction in October, which could lead to a possible delay of 3G services.
Before the earnings announcement, AIS shares were down 2.6 percent, while the broad index was 0.01 percent lower.
AIS, which has the largest share of high-end data users among post-paid customers, should benefit most from growth in data services after the arrival of 3G, analysts said.
New 3G spectrum will enable companies to generate more revenue from fast-growing demand for data services and reduce regulatory costs under a new licensing regime.
($1 = 30.85 baht)
(Reporting by Khettiya Jittapong; Editing by Matt Driskill)