The Stock Exchange of Thailand slightly increased while Singapore shares gave up most of their early gains on Wednesday after data showed factory output growth in August slowed more than expected.
Philippine stocks weakened for a second straight session ahead of an expected rate hike on Thursday.
Investors were also cautious as they weighed how much more policy tightening is in store from the US Federal Reserve. Fed funds rates futures implied traders are fully pricing in a rate hike on Wednesday, plus an 85% chance of another rise in December.
"Asia equity markets had traded defensively in the afternoon session giving back early morning gains... with an FOMC (Federal Open Market Committee) main event on tap tonight, position squaring is dominating market sentiment," Stephen Innes, APAC head of trading at OANDA, said in a note.
The SET index was up 1.94 points or 0.11% to close at 1,749.93, in turnover worth 48 billion baht. The Thai market snapped two consecutive sessions of falls, helped by energy and real estate stocks. PTT Plc rose 0.5% to its highest close in over four months and was among the top boosts.
Singapore's FTSE Straits Times Index climbed 0.9% in intraday trade, before erasing most of the gains to close 0.1% higher, marking its sixth consecutive session of gains.
Manufacturing output in August rose 3.3% from a year earlier, data from the Singapore Economic Development Board showed, slower than the revised 6.7% growth in July. The median forecast in a Reuters survey predicted a 4.4% expansion.
Industrial stocks were the top gainers with Jardine Matheson gaining 1.1%, while Oversea-Chinese Banking Corp was the biggest drag with a drop of 0.5%.
Philippine stocks closed 0.9% lower, making them the top losers in the region.
The selloff was due to a number of factors, including expectations of higher inflation, expected rate hike by the central bank, and macroeconomic factors such as the impact of the trade war and higher oil prices, said Rachelle C. Cruz, an analyst with Manila-based AP Securities.
The central bank is widely expected to raise its key interest rate by another 50 basis points on Thursday, in a bid to tamp down inflationary pressures, which have been steadily rising since January due to higher taxes, a weak peso, and rising food and fuel costs.
The Philippines' finance minister said on Tuesday the main concern for him was the recent rise in oil prices.
Cruz echoed the view, saying the recent rally in oil prices added to pressure on the Philippines which is a net importer of crude.
Indonesian shares reversed their course to close slightly lower, with losses in energy counters outweighing gains in financials.
United Tractors Tbk PT declined 3.2%, while Bank Central Asia Tbk PT rose 1.2%.
"Indonesia's central bank begins their two-day-long policy meeting today with our expectation that the benchmark rate will be increased by 50 bps," OCBC said in a note to clients.