The bank has been conducting its own inquiry into the affair and six staff are already being disciplined.
RBS has been looking at more than 50 former and current RBS traders along with dozens of managers and executives.
The bank was recently fined £400m by the UK and US authorities for its role in the scandal which emerged in 2012.
RBS was one of six banks that were fined £2.6bn last month by the UK, US and Swiss authorities after being found guilty of trying to rig the forex market for several years.
A separate inquiry into the role of Barclays bank and its own forex traders is still underway.
Jon Pain, the head of conduct and regulatory affairs at RBS, said the aim of the bank's inquiry was to "rebuild trust" in the bank.
"We are undertaking a robust and thorough review into the actions of the traders that caused this wrongdoing and the management that oversaw it," he said.
"This is a complicated process but also an essential one in order to identify culpability and accountability for this unacceptable misconduct.
"To be clear, no further bonus payments will be made or unvested bonus awards released to those in scope of the review until it has concluded and its recommendations have been considered," he added.
Two RBS traders were first suspended in October last year.
In a report last month which accompanied the huge fines, the Financial Conduct Authority (FCA) said the attempts to rig the forex market, by colluding with each other to manipulate the daily setting of "spot" prices for individual currencies, had taken place between 1 January 2008 and 15 October 2013.
One man, thought to be a former RBS forex trader, was arrested by City of London police and Serious Fraud Office staff last Friday.
The RBS banking group has withheld bonuses from 18 of the staff it is investigating for their possible role in rigging the foreign exchange market.