The Indonesian rupiah's indicative prices weakened past 11,000 per dollar support on Tuesday, for the first time in more than four years, on dollar demand from local companies after a record trade deficit.
The indicative spot fell 0.7 percent to 11,050 to the greenback as of 0626 GMT, the weakest since April 2009.
(Read more: Is this currency about to follow the rupee's crash course?)
It has been firmer than the 11,000 level since the period, according to Thomson Reuters data.
However, banks in Indonesia have been buying dollars above the level on behalf of their local corporate clients, although the central bank was spotted selling the dollar below that level, traders said.