A spokesperson for ABN told Dutch newspaper Het Financieele Dagblad: "If we don't get the money I expect a revolt."
ABN Amro staff are claiming the loyalty bonuses they would have had for a three-year stint at the bank should now be paid by the RBS after their buyout.
However, the newspaper noted that RBS would face massive difficulties in paying out the cash, since ABN has not included the bonuses on its balance sheet.
An RBS spokesman said the bank had not decided what to do to tackle the bonus challenge but added that employee rights would be respected.
ABN Amro was bought by a syndicate led by RBS, as well as Santander and Fortis for over $100 billion.
According to Here is the City website's Bonus Anticipation Poll, 30.9 per cent of bankers on average felt that their 2007 bonus would be bigger than that paid last year.
Meanwhile over 44 per cent of ABN Amro employees expected a bigger bonus compared to nearly 31 per cent of RBS staff.