Former AFL star Brian Lake could spend much of this month in a Japanese jail after reportedly being arrested due to an incident in a bar.
He could be held for 23 days without charge.
Lake had helped the Indonesian Volcanoes win an Asian AFL tournament and was celebrating in the bar when he was arrested, according to News Corp.
The Department of Foreign Affairs and Trade have confirmed an Australian in Japan might need their help, without providing any more details.
"DFAT is making inquiries about an Australian in Japan who may require consular assistance and stands ready to provide assistance ... should it be requested," a spokesperson said.
"Owing to our privacy obligations we will not provide further comment."
Former motorcycle world champion Wayne Gardner was detained for 12 days in Japan two years ago after an alleged road rage incident.
Earlier this year, former Wallabies rugby star George Smith spent 20 days in a Tokyo jail after an altercation involving a local taxi driver.
He was released without charge.
Lake played 251 AFL games, including 197 for the Western Bulldogs before he switched to Hawthorn.
He won the Norm Smith Medal as best on ground in the Hawks' 2013 grand final win over Fremantle.
Lake retired in 2015 and now works part-time in the media.