A football fan who threw a banana at Adelaide Crows' star Eddie Betts has been fined for disorderly behaviour by South Australian police.

The 27-year-old woman from southern Adelaide has been fined a total of $543 and issued with a police barring order for six months.

The Port Adelaide supporter released a statement via the football club on Monday apologising to Betts and said she would take part in the club's cultural awareness program.

Police said the ban meant the woman could not go into the Adelaide Oval "entertainment precinct" for any activity.

She was caught on camera throwing a banana onto the Oval last Saturday night, just after Betts had scored a goal.

The Indigenous Crows player said on Monday it was sad racism still existed, and he asked people to speak with their children and others about the issue.

"Hopefully people can learn from it," he said.

Betts scored five goals in the Showdown, his 250th AFL game, as the Crows beat Port by 15 points and moved to second on the premiership table with one round until the finals.

The woman who threw the banana said she was sorry she ruined the Showdown for so many fans and would accept the sanctions given to her.