The central bank said in a circular dated July 10 that daily placements with it by lenders above 2 billion naira ($6.5 million) would not earn interest.
The latest rule, which takes effect from Thursday, is the second in a week targeted at increasing credit to businesses and consumers. The central bank is seeking to boost loans by trying to force banks to lend after a recent recession.
Nigeria’s economy has since recovered from that contraction, but lending has not returned as growth is slow and banks prefer to invest in risk-free government securities or pack cash with the central bank for a fee rather than lend.
Last week the central bank asked banks to lend more or face higher cash reserve requirements, part of a series of measures aimed at reviving an economy stuck with low growth.