Philip Hampton, chairman of the organisation - which is the biggest government-controlled bank in Britain - said this will come about as a result of the Independent Commission on Banking's (ICB) plan to install fire breaks around retail banks.
In a statement, the industry figure noted: "We will have to work hard to mitigate the impact of additional costs arising from the ICB changes. It seems inevitable that customers and shareholders will be impacted by additional costs."
Mr Hampton added that a recovery at RBS is underway at present, as the bank has its sights focused on a return to profit on the back of three years of losses.
RBS recently noted a backlash was expected from shareholders who do not agree with the company's executive pay plans.
By Asim Shah