Acting on a tip-off, police intercepted a car at Parsik circle in Mumbra township of Thane district at around midnight on Tuesday.
They found Rs 1 crore in old Rs 500 and Rs 1,000 demonetised notes in possession of three persons, including a woman employee of a private bank, an official release issued by Thane police said today.
The three persons were planning to get the notes exchanged for new ones. They were later arrested and a case was registered against them under relevant sections, Thane police PRO Sukhada Narkar said.
Police are trying to find out how the accused got possession of the junked notes, Mr Narkar said.