Bank Indonesia tightened rules on dollar purchases to prop up the rupiah after the currency slid to new lows, warning it will intensify intervention in both onshore and offshore foreign-exchange markets. Governor Perry Warjiyo called the rupiah "undervalued and should strengthen moving forward," pledging a stronger central bank response.

Under the new measures, monthly domestic dollar purchases will be limited to $50,000 per person, down from $100,000, unless buyers can demonstrate a legitimate need for larger amounts. DBS senior economist Radhika Rao said the move aims to ensure dollar purchases are backed by genuine underlying needs rather than speculative activity.

The rupiah strengthened slightly after BI's announcement. The dollar reached 17,410 rupiah on Wednesday after touching 17,445 the prior session, LSEG data shows. The central bank will also coordinate with the finance ministry to buy government bonds on the secondary market to maintain adequate liquidity and strengthen capital flows.