The DRI officials intercepted the woman when she was on a flight to Hong Kong on Monday, the agency said in a statement.
"During examination of her checked in and hand baggage, $4,80,200 wrapped in aluminium foil with a market value of Rs 3.25 crore, has been recovered," it said.
During interrogation, it came to light that the woman was a carrier for a major international hawala syndicate and has carried foreign currencies many times for a Delhi-based hawala operator, the statement said.
The operator, identified as Amit Malhotra, is a resident of Vivek Vihar area in Delhi, a senior DRI official said.
He said Mr Malhotra would smuggle forex out and into the country with the help of airline crew members.
"Amit Malhotra would collect money from some bullion dealers in Delhi and send it through some air hostess to select foreign destinations. The money was being used for purchasing gold abroad. The gold would then be sent to India illegally," the official said.
The DRI suspects some other crew members of Jet Airways may also be involved in smuggling out forex, the official said.
"Amit Malhotra has been illegally smuggling forex for over one year. There are some other crew members involved in the case. We are also trying to find out the details of bullion dealers involved in this syndicate," he said.
Both Malhotra and the Jet Airways crew member have been arrested, the official said.
A Delhi court sent the two to two-day judicial custody.
The DRI has recovered Rs 3.3 lakh in cash, and foreign currencies of different countries worth $2,500, besides several incriminating materials from Mr Malhtora, he said.