EMERGING MARKETS-Asian FX firm; Thai baht and Indonesian rupiah jump on investor optimism

* Indonesian rupiah hits five-week high * S.Korean won marks best day since start of December * Thai baht snaps three-day losing streak * Regional equities higher; Philippine shares advance over 1% By Sameer Manekar Dec 23 (Reuters) - The Thai baht and Indonesian rupiah rose more than half a percent each on Thursday, buoyed by an optimistic view of the global economic outlook even as the world continues to grapple with uncertainty around the Omicron coronavirus variant. Thailand's baht firmed up to 33.57 per dollar, breaking a three-day losing streak and marking its best day in two weeks, while the Indonesian rupiah extended gains into a third session to hit its highest since Nov. 19. The safe-haven dollar languished near an almost one-week low against its major peers as investors looked beyond the surging cases of the Omicron variant. The dollar index stood at 96.061, not far from its overnight low of 96.020. Global markets, including all three major indexes on Wall Street, recorded strong gains supported by positive economic data and hopeful developments around COVID-19. A South African study suggested Omicron is much less likely to cause hospitalisation than the Delta strain, offering a glimmer of hope to markets. Meanwhile, the United States overnight authorised Pfizer Inc's antiviral COVID-19 pill for people ages 12 and older. "The (Asia) region has largely struggled to catch on to the bullish momentum from its U.S. counterpart recently, and the gains in today's session seem to lag in terms of magnitude as well," Yeap Jun Rong, market strategist at retail trading platform IG said. However, analysts at Mizuho Bank struck a cautious note, saying that as the holidays approach, "we should take heed not to over-indulge in growing optimism, especially with volatility swinging between COVID-19 spread and severity". Elsewhere in Asia, the South Korean won strengthened 0.5% to 1,186.10 per dollar, their best day since the start of the month, while the Malaysian ringgit, Singapore dollar and Taiwan's dollar logged decent gains. Thailand's central bank on Wednesday left its key interest rate steady at a record low, but cut its 2022 growth outlook, saying it expected the Omicron variant to impact the economy early next year. On Tuesday, the Thai government reinstated its mandatory COVID-19 quarantine for foreign visitors, having only reopened to foreign tourists last month. Later that day, it approved a new package of economic stimulus measures including tax breaks for shoppers, as it looks to revive an economy struggling with the pandemic-induced collapse of its vital tourism sector. "With Omicron delaying regional reopening plans, the recently approved stimulus package which includes tax deductions for shopping, will be timely to lift private consumption in early 2022," Mizuho Bank analysts said. All regional equities traded higher, with Philippine shares advancing more than 1% after three straight days in the red, while Singapore, Malaysia and Indonesia each added about 0.5%. HIGHLIGHTS: ** Indonesian 10-year benchmark yields flat at 6.400% ** Union Bank of the Philippines to buy Citi's Philippine consumer banking business ** Philippines approves use of Pfizer vaccine in children aged 5-11 Asia stock indexes and currencies at 0328 GMT COUNTRY FX RIC FX FX INDE STOCK STOCK DAILY YTD % X S S YTD % DAILY % % Japan +0.00 -9.53 <.N2 0.31 4.40 25> China EC> India 0.00 -3.29 <.NS 0.00 21.27 EI> Indones +0.28 -1.44 <.JK 0.31 9.55 ia SE> Malaysi +0.21 -4.35 <.KL 0.47 -7.36 a SE> Philipp -0.02 -4.19 <.PS 1.07 0.78 ines I> S.Korea 11> Singapo +0.09 -2.88 <.ST 0.30 8.89 re I> Taiwan +0.16 +2.55 <.TW 0.60 21.73 II> Thailan +0.51 -10.7 <.SE 0.71 13.04 d 8 TI> (Reporting by Sameer Manekar in Bengaluru; Editing by Ana Nicolaci da Costa)