Angolas central bank said on Tuesday it will sanction seven financial institutions for failing to comply with foreign exchange rules, but did not state the specific breaches or the sanctions it would take.
In a statement posted on its website, the central bank named the banks, which include Angolan Bank SA Investments and the local unit of Johannesburg-listed Standard Bank.
The banks were not immediately available to comment.
The bank currently quotes the kwanza at 166.711 per dollar, although the currency typically trades at much weaker levels in the black market due to chronic shortages.
Angola's economy has been hammered by the drop in crude prices and an acute hard currency crunch, fueling a thriving black market for the currency of Africa's top oil exporter after Nigeria whose output has dropped after attacks on its pipelines.
In April the central Bank of Angola said it had cut the amount of hard currency travellers could take abroad to $10,000 from $15,000, under new rules to cope with a decline in foreign exchange reserves.