Warne captained the Melbourne Stars throughout the league but passed the captaincy to teammate James Warner in a semifinal against the Perth Scorchers to avoid a possible suspension for Melbourne's slow over rate.
Cricket Australia deemed the captaincy switch to be a code of conduct violation after previously warning teams ``if a team's official captain is selected but not named as captain...this may attract a code of behavior charge.''
Warne had previously been warned over Melbourne's slow over rate and faced a one-match suspension for a second offence.
``I had no idea about the rule/law,'' Warne tweeted. ``If I was aware of the law/rule I would have tossed the coin.
``I should have been informed and made aware by management. Anyway, disappointed it was not a Stars fine rather than me as I was never informed.''
Melbourne Stars chief executive Clint Cooper said he accepted Warne was not aware of the captaincy rule.
Cooper said he and team manager Ben Robertson ``equally shoulder the responsibility of the breach given the miscommunication between team management and Shane Warne.
``We hope this blemish on Shane's record doesn't overshadow what he has contributed and achieved in the game over the last 25 years.''