Bank Indonesia (BI) will ensure exchange rate stability by "intervening in the DNDF (domestic non-deliverable forward), government bond and FX spot markets," the bank's head of monetary management Nanang Hendarsah told Reuters.

BI will also offer banks term repo to provide rupiah liquidity in the interbank money market, if necessary, Hendarsah said.

The rupiah weakened 0.45 percent on Monday to 14,530 to the dollar, following last week's 1.2 percent drop. Most Asian currencies were under pressure in recent days due to skepticism over a truce in the U.S.-China trade war.