Bars were shut and football matches cancelled as President Edgar Lungu led the country on a national prayer session at the Heroes Stadium in Lusaka, the capital of Zambia, where about 85 percent of the population are Christians.
Food prices have soared and crippling power shortages have also been triggered due to low water-levels in Lake Kariba, where the hydropower plants that supply much of the country's electricity is located.
"God is a god of miracles and if we ask him, he will bless us and the kwacha (nation’s currency) shall be restored to its former strength and the prices of goods shall again go down," Bishop Simon Chihana, president of the International Fellowship of Christian Churches in Zambia, said.
"Let's pray to God to have mercy on us. God has done that before and he can do it again."
Critics of the government have accused Lungu of failing to tackle the causes of country's economy troubles, saying that the prayer day was a distraction.
Zambia is Africa's second biggest copper producer but a collapse in global copper prices has seen its kwacha currency tumble nearly 50 percent against the dollar this year.
Lungu came to power in January after the death of President Michael Sata last year.