Andre Gumprecht, 33, attended the post-final ceremony for his Central Coast Mariners team dressed in a khaki military uniform, along with a toothbrush moustache.

"Hitler was such a monster and for a lot of people, it's a very sensitive thing to be confronted with," said Ernie Friedlander, spokesperson for the Jewish community group B'nai B'rith.

"Even if it was done in jest, he is a role model and he should consider the impact of his actions," said Allon Lee, head of the Australia/Israel & Jewish Affairs Council.

The head of the Football Federation Australia (FFA) condemned the gaffe, stating that he would be demanding an explanation from Gumprecht.

"Such behaviour is not only stupid, but is also not tolerated by the FFA," said Ben Buckley, chief executive of the sports regulator.

With news of the scandal causing controversy in his native Germany, Gumprecht wrote an apology to the German people in the form of an open letter.

"My intention was solely to entertain, not insult and any suggestion that I might somehow be trying to support Nazi ideals or behaviour is simply ridiculous," Gumprecht wrote.

"I would also extend that heartfelt apology to everyone in Germany who might feel embarrassed or annoyed by my actions here in Australia."

"I have since apologized unreservedly and often for any offence caused to anyone here who might have been upset by my costume."

Gumprecht uses the letter to explain the rationale behind his choice of costume.

"In this country, the day after a big achievement -- e.g. being grand finalists -- a team will celebrate by enjoying a few beers in costume," he wrote.

"In the spirit of fun, the team, as a group, will decide on a costume for each player."

"This costume will be dependant upon that player's personality and their public perception."

"Given the sense of humour of Australians, this usually means something that makes fun of the player and can border on bad taste."

"Given my German heritage, plus my committed approach on the field, it was decided that I should go as Hitler."

"As it was meant in the spirit of fun, I admit I never gave it much thought, although I didn't wear any Nazi insignia or trappings."

Whilst pointing out that his fellow players selected his costume, Gumprect accepted his responsibility for the gaffe.

"It should be understood that I am not seeking to pass the blame."

"I realize that I am ultimately responsible for my decisions and actions and that on this occasion, I made a mistake."

"I unreservedly apologise for my apparent insensitivity and lack of forethought and any offence caused."

"I can assure you that I will consider my actions much more carefully in the future."