Mr Hester made the comments in an interview with Welt am Sonntag, a German newspaper.
RBS headed up a consortium, which included Fortis and Santander, to acquire the Dutch bank for â¬71 billion in 2007.
However, the decision to go-ahead with the takeover was viewed by many industry commentators as one of the reasons behind the financial institutionâs weakness and subsequent reliance on government funds when the credit crisis occurred a year later.
The RBS CEO told the newspaper that his predecessor, Sir Fred Goodwin, failed to implement a coherent strategy when he opted to acquire the Dutch business.
Mr Hester also said that he would be âdisappointedâ if the British government did not start selling down part of its 83 per cent stake in the bank by 2011.
He added that the sale would be a gradual process rather than occurring all at once.
The bank is currently in the process of divesting itself of non-core business assets to boost its balance sheet.
By Jim Ottewill