The rupiah weakened by 0.9 percent to 14,425 per dollar at 0610 GMT, after hitting its best level since June earlier this week.

"(BI) has not entered the market up to now. There is still time until 16.00," Hendarsah said, referring to market closing time.

Most Asian currencies weakened on Wednesday as optimism over a U.S.-China trade truce fades.