Three Olyroos will miss Tokyo 2020 after Football Federation Australia suspended them until August 2020 over "unprofessional conduct" involving a woman in Cambodia in March.
Nathaniel Atkinson, Lachlan Wales and Brandon Wilson will all miss the Olympics, but star striker Riley McGree ducked the full ban and will be eligible for selection after he received a shorter suspension.
McGree's suspension ends in April, while the rest will be banned for a further six months.
However all four will be suspended for January's AFC U23 Championships in Thailand which doubles as qualification for Tokyo 2020.
Full details of the incident sparking the bans were not revealed by the FFA.
But a statement confirming the suspensions said: "The sanction follows a finding that the players have engaged in conduct in breach of the Code of Conduct during the AFC U23 Championship qualifying tournament in Cambodia in March this year.
"Specifically, the FFA Board found that the players engaged in unprofessional conduct."
It added: "The matter came to the attention of FFA in April 2019 following a complaint by a woman.
"FFA initiated an independent investigation shortly after the complaint was received and due to its complexity, the investigation took months to complete.
"The FFA Board considered the findings of the investigation in early October 2019 and subsequently determined to initiate its Code of Conduct process, which involved providing each player with the opportunity to make submissions to FFA on the alleged breaches of the Code of Conduct.
"FFA considered those submissions, including submissions made by Professional Footballers Australia, in reaching its determination which was communicated to the players today."
All the players will also be ordered to take educational and counseling sessions in the wake of the incident.
Puskas Award nominee McGree has been in sensational form for Adelaide United this season, striking four times in five games in the A-League and twice more in the FFA Cup.
Wales has been a regular for Melbourne City but team-mate Atkinson has struggled for gametime, as has Wilson for Perth Glory.
“These sanctions are commensurate to the nature of the breaches of the National Code of Conduct which is in place to safeguard both the players and the reputation of Australian football," said FFA chairman Chris Nikou.
“Upholding our commitment to respect and responsibility cannot be compromised. Our game is built on equality, inclusivity and respect and these are values that we will continue to uphold.
"The players have understood the gravity of their actions and have positively commenced respectful relationship programs that will ensure they appreciate these values in the future.”
The players can appeal the suspensions.