Atiku Abubakar, the opposition candidate for president of Nigeria, appealed the central bank on Saturday to postpone the deadline for phase-out of outdated high-value banknotes until beyond January 31. Many Nigerians worry that this move will cause economic disruptions in the country’s cash-based economy.

By Tuesday, 1,000 ($2.17), 500, and 200 naira notes must be returned to Nigerians or they would lose their legal tender status. Newly designed notes have been released by the central bank since last month, but many Nigerians claim that banks do not currently have them in stock.

The Central Bank of Nigeria (CBN) says recalling the notes is part of plans to reduce the use of cash. About 1.3 trillion naira in old notes has been deposited into the bank since the announcement in October, the bank said this week.

However, in Africa’s biggest economy Nigeria, most people live in rural areas and the biggest employer is the informal sector where cash is used for most transactions.

Atiku, the main opposition People’s Democratic Party’s candidate in next month’s presidential election, said it would be impossible for most of Nigeria’s unbanked population to turn in their old notes in time.

“I’m aware of the challenges that farmers and others like artisans in remote areas of the country go through in moving cash to commercial banks for the conversion,” Atiku said in a video.

“It is important for the CBN to consider an extension of the time that the public convert their bank monies into new notes, thereby reducing the financial consequences for citizens.”

Nigerian legislators have also asked the central bank to extend the Tuesday deadline.

In Lagos, some shops were rejecting old banknotes at the weekend in anticipation of the deadline.