The Reserve Bank of India (RBI) on Wednesday asked banks to stop circulating some notes of Rs 1,000 denomination after it received complaints that the notes lacked the security thread.

"We have received complaints regarding bank notes in the denomination of Rs 1,000 printed by Currency Note Press, Nashik, on the paper (without the security thread) supplied by Security Paper Mill (Hoshangabad)," an RBI spokesperson was quoted as saying by the Press Trust of India.

Banks in the Mumbai region were asked by the RBI not to issue these faulty notes if found they are in the stock. The bank also said customers who approach the banks with the faulty notes should be provided exchange value — if otherwise genuine.

According to an RBI spokesperson, the total number of faulty notes were not more than 500, which means the total value of the notes would be approximately Rs 5 lakh.

"We have also escalated the matter to the government," the spokesperson added.

Currency Note Press, Nashik, is a unit of the Security Printing and Minting Corporation of India Limited (SPMCIL), and is under the control of the Finance Ministry.