* Singapore at near 8-wk high after strong 2010 GDP data
* Indonesia at over 3-wk high; Philippines at near 4-wk high
* Thin volume trading in Singapore, Jakarta
By Shihar Aneez
COLOMBO, Jan 3 (Reuters) - All southeast Asian stock markets gained on Monday, the first trading day of 2011, with Malaysia hitting a record high and Singapore rising to a near eight-week high after posting strong economic growth data for 2010.
Malaysia gained 1 percent to an all-time high close of 1,533.42 points, surpassing its previous record high hit on Nov. 10. The trading share volume in Kuala Lumpur was more than its 90-day average volume.
Singapore outperformed regional markets with 1.4 percent gain, its highest percentage and points rise since Nov. 1, after its government posted Asia's fastest economic growth of 14.7 percent for 2010.
Indonesia, the region's top performer in 2010, gained 0.7 percent, its highest since Dec. 10, while Philippines edged up 0.3 percent to a near four-week high.
Both Thailand and Vietnam were closed on Monday for an extended new year holiday.
"Some degree of new year optimism helped the markets to gain," said Song Seng Wun, a Singapore-based regional economist at CIMB-GK Research.
"2011 will be a year where investors will be looking for more macro-economic stability. Inflation and policy risks will be the main concerns for investors in the region."
Analysts said investors are still bullish on valuations of regional markets, with potential high growth in corporate earnings this year.
Indonesia is trading at 14.8 times projected earnings, the highest in the region and compared with all-Asia's 13.0. Thailand is trading at 12.3, lower than the 13.8 of Malaysia, 13.7 of Singapore and 13.2 of the Philippines, Thomson Reuters StarMine data shows.
In Singapore, top lender DBS Group rose 1.3 percent, while United Overseas Bank added 2 percent on the day.
Oversea-Chinese Banking Corp gained 1.4 percent after it said the merger of its two licensed bank subsidiaries in Indonesia -- Bank OCBC Indonesia and Bank OCBC NISP -- had taken effect from Jan. 1.
Expected high prices for palm oil helped Golden Agri-Resources to gain 2.5 percent, Indofood Agri Resources to close 3.2 percent firmer and lift First Resources 1.9 percent.
In Jakarta, mining shares drove up the overall index, with a 7 percent rise in Indo Tambangraya Megah Tbk, a 4.9 percent gain in Adaro Energy and a 3.3 percent rise in top minor Bumi Resources.
In Manila, conglomerate San Miguel Corp surged 13 percent after announcing its wholly owned Vega Telecom Inc unit has bought a company that owns 40 percent of Eastern Telecommunications Philippines Inc (ETPI). (Editing by David Holmes)