The official exchange rate had previously stood at 55 pounds to the dollar, while the black market rate had been fluctuating recently between 350 and 400 pounds.
The vast western region of Darfur was convulsed by bloody fighting in 2003. It killed 300,000 people and displaced 2.5 million, according to the United Nations.
Bashir, who is currently in custody in Khartoum, is wanted by the International Criminal Court for alleged genocide and war crimes in Darfur perpetrated more than a decade ago.
Ethiopia sees the dam as key to plans to become Africa's largest power exporter. Egypt, which gets more than 90% of its scarce fresh water from the Nile, fears the dam across the Blue Nile could devastate its economy.
In early December Sudan accused Ethiopian "forces and militias" of ambushing Sudanese troops along the border, leaving four dead and more than 20 wounded.
Refugees are continuing to flee the unrest in Ethiopia's northern Tigray region, with 800 having crossed the border with eastern Sudan since the New Year.