Khartoum: Sudan was Sunday expected to start circulating its new currency, the central bank said, days after South Sudan started rolling out a currency of its own.

South Sudan, which declared independence on July 9 under a 2005 peace deal that ended decades of civil war, said last Monday it had started circulating its new South Sudan pound, pegging it one-to-one with Sudan's existing pound.

The northern central bank had previously said it would take up to three months to replace the old Sudanese pound, describing the currency move as a "precautionary measure" following the southern plans.

Exchange crisis

The Sudanese pound has been falling on the black market in Khartoum for weeks as economists say foreign currency inflows needed for imports will decline alongside falling oil revenues.

The old pound has also fallen in the south on worries the old notes will be worthless if both countries do not reach an agreement to coordinate their currency launches.

The south took about 75 per cent of Sudan's 500,000 barrel-a-day oil reserves with it when it left.