Indonesia's biggest tobacco company PT Hanjaya Mandala Sampoerna Tbk's shares clocked their best performance in almost a year after it reported a near 11% jump in first-half net income.

Broad-based gains pushed the Jakarta index to its biggest intraday rise in six weeks during the session.

Cigarette makers in Indonesia have suffered since US-based e-cigarette brand Juul was introduced on July 10, with Hanjaya's stock price slipping over 10% since, as of last close.

"It's more of a technical rebound after 4 to 5 sessions of weakness that we've seen. I think it's more of bottom fishing for some stocks," said Taye Shim, head of research at Mirae Asset Sekuritas.

Meanwhile, most other Southeast Asian markets edged lower ahead of the US Federal Reserve meeting, where it is widely expected to ease its monetary policy. Investors are also eyeing the central bank chief Jerome Powell's speech for further direction.

A quarter-point cut has mostly been factored in but recent upbeat US data, such as jump in second-quarter GDP, has dimmed chances of an aggressive rate-cut.

Vietnam's main board lost 1.2%, underpinned by losses in real estate and financial sectors.

Philippine shares declined 0.5% on weakness in financial and industrial stocks, but the benchmark is on track to close higher for the fifth straight month.

Thai stocks slipped to their lowest in over a month after government data showed its factory output declined more than expected in June.

The country's manufacturing production index (MPI) in June fell 5.54% from a year earlier, dragged down by lower production of cars, rubber products and petroleum, while a Reuters poll predicted a drop of 3.15%.

Among shares, construction material supplier The Siam Cement PCL and Global Power Synergy PCL were among top laggards on the benchmark.

Singapore shares were little changed, while Malaysian stock market was closed for a holiday.