SE Asia Stocks-S'pore near 2-wk highs; Thailand at 15-mth peak

* S'pore banks advance after Q3 GDP

* Thailand, Vietnam rise for a fifth day

* Malaysia nearly flat, Indonesia extends losses

BANGKOK, Oct 12 - Singapore stocks climbed to their highest in almost two weeks on Monday after surprisingly third quarter economic growth sprked buying in banking shares, the Thai index scaled a fresh 15-month high.

Singapore's benchmark Straits Times Index ended up 1.1 percent at its highest level since Sept. 30, with DBS Group, Southeast Asia's biggest lender, up 0.8 percent, after the central bank announced no change in its monetary policy stance and better-than-expected GDP growth in the third quarter.

"The latest figures show that the worst is over for the Singapore economy," said Yip Yee Lan, an economist at BNP Paribas.

The news boosted other bank stocks such as Oversea-Chinese Banking Corp which gained 0.8 percent and United Overseas Bank which climbed nearly 2 percent.

Singapore Exchange gained 0.8 percent ahead of its earnings release scheduled for Thursday.

The bourse operator could show a quarterly net profit of S$96 million ($69 million), up 5.3 percent from the previous quarter, said Daiwa Institute of Research analyst David Lum in a note to clients.

Indices in Singapore, Thailand and Vietnam each extended gains for a fifth day. Thailand added 0.7 percent, coming off its early rise to its highest since July 3, 2008.

Vietnam climbed 2.1 percent, erasing some of its early gains to its highest since March 17, 2008, with real-estate developer Hoang Anh Gia Lai up 3.3 percent and steel maker Hoa Phat 2.8 percent higher.

In Bangkok, foreign buying momentum continued from last week while some analysts expected a market correction soon.

"It seems as if foreign fund flows to Thai stocks have continued unabated. Foreign investors went on a buying spree on the Thai bourse," said Phillip Securities analyst Teerada Charnyingyong.

"In our view, the more the market rally has run too far ahead of economic reality, the higher the risk of profit taking grows," she said.

Among outperformers, True Corp jumped nearly 8 percent after a newspaper reported state run CAT Telecoms would join hands with its mobile phone subsidiary True Move to bid for a long-awaited third-generation (3G) spectrum.

PTT Exploration rose 2.3 percent on higher oil prices and after announcing its Bongkot offshore gas field was expected to finish gas pipeline repairs on Oct. 19 and resume its gas deliveries by then.

Malaysia inched down 0.04 percent, after a three-day rise, Indonesia fell for a fourth day, sliding 0.7 percent while the Philippines lost 0.4 percent, adding on a 0.9 percent decrease on Friday.

In Kuala Lumpur, palm plantation firm IOI Corp was down 0.4 percent, erasing some early losses after Moody's Investors Service changed the outlook of IOI Corp to stable from negative.

Financial CIMB Group dipped 1.5 percent while Telekom Malaysia fell almost 1 percent.

In Jakarta, which touched its lowest since Oct. 2 earlier, Bank Rakyat off 3.1 percent and Bank Mandiri 1.5 percent lower. In Manila, Ayala Land and Metropolitan Bank each lost more than 2 percent. ($1=33.32 Baht) (Additional reporting by Saeed Azhar in Singapore)