Norway's central bank said on Wednesday it would sharply increase its purchase of foreign currency for its sovereign wealth fund in September, amid a surge in the country's oil and gas revenues.

Norges Bank plans to exchange 3.5 billion Norwegian crowns ($355.41 million) per day into foreign currency, up from 1.5 billion per day in August, which will in turn be invested abroad by the wealth fund. ($1 = 9.8477 Norwegian crowns) (Reporting by Terje Solsvik, editing by Stine Jacobsen)