Veteran Australian leg-spinner Shane Warne has been fined $5,000 for acting "against the spirit of cricket" during the Melbourne Star's Big Bash League semi-final clash against the Perth Scorchers last week.

Warne captained the Melbourne franchise throughout the competition but, to avoid a possible suspension for a slow over-rate contravention, passed the captaincy to team-mate James Faulkner for the match against Perth.

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 behaviour 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," tweeted Warne. "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."