April 25 (Reuters) - A look at the day ahead in Asian markets.

The depreciation of Asian currencies against the U.S. dollar, and the steps monetary authorities may take to prevent further weakness, dominate the market landscape across Asia on Thursday as the Bank of Japan gets its two-day policy meeting underway.

The regional economic data highlights include South Korea's first quarter GDP, Malaysian consumer price inflation for March, and the latest trade figures from Vietnam and Hong Kong.

After-the-bell earnings from U.S. tech giant Meta on Wednesday could weigh on Asian markets - shares plunged 10% in after-hours trade.

Sentiment is fragile: some stock markets have recovered around half of their recent losses but Meta's slump throws a cloud over that, while U.S. bond yields spiked following a weak auction of five-year notes.

Unease around currencies is deepening after the dollar on Wednesday smashed through 155.00 yen with no sign of Japanese authorities to slow or reverse the yen's fall. Will Tokyo act?

An executive from Japan's ruling LDP told Reuters the party is not yet in active discussion on what yen levels would be deemed worth intervening in the market, but a continued slide towards 160 or 170 to the dollar could trigger action.

It's hard to imagine the Ministry of Finance letting the dollar go to 160 never mind 170 yen before intervening. Then again, few would have imagined there would be no intervention at 155 yen either.

Will MOF instruct the BOJ to wade into the FX market and buy yen just as the central bank starts its two-day policy meeting?

In the current climate, which prompted a rare three-way joint statement on exchange rates from the United States, Japan and South Korea this month, nothing can be ruled out.

In the realms of surprises, Indonesia's rate hike to counter the weakness of the rupiah would have caught many market participants off guard. The currency's subsequent 0.4% bounce was modest, but was the biggest in seven weeks and enough to pull it further from last week's four-year low.

There will be more than a few grumbles across Asia at Tokyo's reluctance to anchor the yen, which is giving a huge competitive boost to Japan - the yen is at a 31-year low against China's yuan and close to multi-year lows against the currencies of South Korea, Thailand, Vietnam and others.

India's central bank has intervened regularly recently to support the rupee and Bank of Thailand officials said on Wednesday the BOT intervened to ease excessive moves in the baht.

U.S.-Sino relations took another twist after the U.S. Senate voted in favor of legislation that would ban TikTok in the United States if its Chinese owner ByteDance fails to divest the popular short video app over the next nine months to a year.

Here are key developments that could provide more direction to markets on Thursday:

- Bank of Japan begins policy meeting

- South Korea GDP (Q1)

- Malaysia inflation (March)

(Reporting and Writing by Jamie McGeever; )