McCullum was found guilty of dissent by Match Referee Mike Procter in a hearing held after Sri Lanka's six-wicket victory over New Zealand.
He was found to have breached 1.3 of the ICC Code which relates to ''Showing dissent at an umpire's decision by action or verbal abuse''.
The New Zealand wicketkeeper-batsman pleaded guilty to the charge and apologized to the umpires concerned during the hearing.
The offence related to his reaction when he was given out lbw by umpire Asad Rauf.
All Level 1 breaches carry a minimum penalty of an official reprimand and a maximum penalty of 50 per cent of the player's match fee.
The charge was brought by on-field umpires Asad Rauf and Billy Doctrove and television umpire Aleem Dar. Mr Procter reached his conclusion after a hearing attended by New Zealand team manager Lindsay Crocker and coach John Bracewell.
For Level 1 breaches of the ICC Code of Conduct, the Match Referee's decision is final and binding.