The naira dropped to 382 against the United States dollar at the parallel market on Monday, down from the 380 it closed on Friday.
The local currency had hovered between 375 and 380 against the greenback last week.
The naira has been under a persistent pressure as dollar scarcity continues to weigh on the local currency at both the parallel and interbank forex markets.
The CBN had asked for quotes of $5m each from currency traders on Wednesday as it sold the US currency to boost dollar liquidity and support the naira, traders said on Monday.
The naira opened at 315 to the dollar and weakened to 324 before the central bank intervened to help the currency close at 316.37. A total of $27.05m was traded on Monday, Thomson Reuters data showed.