The sum, which has been agreed by HM Treasury but requires Parliamentary approval, is equivalent to 60% of the department’s current annual budget of £32m.
The organisation said that the money is needed to help pay for investigations into engineering firm Rolls-Royce, a deal between Barclays and Qatar, and alleged manipulation of the Libor benchmark interest rate.
Some of the funds will also be put towards paying for litigation in connection with its failed inquiry into property tycoons the Tchenquiz brothers, who are suing the organisation for damages.
That case is the latest in a number resulting in embarrassment for the SFO. In December, it was forced to drop an investigation into bribery claims against Victor Dahdaleh, after spending an estimated £1.4m on the probe. And last year it was reprimanded for making large payments to departing executives without HMT approval.
Solicitor general Oliver Heald told Parliament that, if it agreed the sum, urgent expenditure estimated at £11m would be immediately covered using loans from the government’s contingencies fund.