The Italian football federation (FIGC) in June granted Serie A permission to stage the game in Perth next February while Milan's San Siro stadium is being used for the Winter Olympics opening ceremony, although UEFA and FIFA still need to give their approval.
With Spanish clubs Villareal and Barcelona also proposing to stage a regular season La Liga match in the American city of Miami in December, EU Sports Commissioner Glenn Micallef said the unprecedented moves were a "betrayal of the fans".
"I'm deeply disappointed by proposals to stage domestic league matches outside Europe," the Maltese official wrote in a thread on social media platform X on Wednesday.
"To me it's clear: European competitions must be played in Europe. European football must stay in Europe.
"I believe that clubs owe most of their success to their loyal fans & local communities ... moving competitions abroad isn't innovation, it's betrayal."
In a statement, Serie A said it was "astonished" by Micallef's remarks, adding he underestimated "the complexity and strategic value of initiatives aimed at promoting Italian football on a global scale".
"To speak of betrayal for a single match, out of a total of 380 Serie A matches, seems an excessive position, which risks fuelling a populist debate," the statement continued.
"Taking a match abroad does not mean exporting the championship, but rather introducing new audiences to the excellence of Italian football.
"In return for a small sacrifice required of the Milan and Como fans, (they) will ... benefit in terms of increased visibility and popularity worldwide."
Spain's LaLiga President Javier Tebas said there were "thousands of fans, including Europeans" around the world deserved to see their teams play live.
"I understand the concern, but we need to put things into perspective: we are talking about one match out of 380," Tebas wrote on X.
"I am surprised that there is not as much alarm about projects such as the NBA-FIBA European league — which do fundamentally disrupt the European sports model — or about piracy, which is ruining many professional competitions."
