The Sudanese pound had mostly stabilised in recent months after being sharply devalued in February 2021 as part of economic reforms carried out by a transitional government and monitored by the International Monetary Fund.
Sudan's inflation rate, one of the highest globally, had also begun to ease. In December it continued a downward trend, dipping to 318% year-on-year from 339.5% in November, the national statistics agency said.
Military leaders dissolved the transitional government in the coup before bringing back Prime Minister Abdalla Hamdok in an attempt to protect the reforms, but he resigned earlier this month.
"People are buying dollars to protect their assets, fearing a deterioration of the situation in the country and there's big demand," said one trader in the capital Khartoum.
Dollars had been selling for about 450 pounds last week. The gap between the parallel market and official exchange rates had mostly been negligible in the past few months.
Last week the United Nations began consultations https://www.reuters.com/world/africa/un-says-dialogue-solve-post-coup-crisis-sudan-start-immediately-2022-01-10 to try to break a deadlock between military leaders and pro-democracy civilian groups and avert the risk of further instability.
Much of the international backing for Sudan's economic reforms was suspended https://www.reuters.com/markets/us/exclusive-sudan-cut-off-650-million-international-funding-after-coup-2021-12-08 after the coup. A long-running economic crisis triggered the uprising which toppled autocratic former leader Omar al-Bashir in 2019.
(Reporting by Khalid Abdelaziz; Writing by Aidan Lewis; Editing by Andrew Cawthorne and Raissa Kasolowsky)
