Under Japanese law, Lake can be held for up to 23 days without charge. The Department of Foreign Affairs and Trade confirmed it was working to help him.

"The Department of Foreign Affairs and Trade is making inquiries about an Australian in Japan who may require consular assistance and stands ready to provide assistance, in accordance with the Consular Services Charter, should it be requested. Owing to our privacy obligations we will not provide further comment," a DFAT spokesperson said.

Lake's manager, Marty Pask of i50 management, said his company was still gathering information, and that Lake was assiting authorities with their inquiries.

"Given the international constraints involved and out of respect to local governance, we won't be commenting further at this stage," Pask said.

"We do ask that the privacy of Brian's wife and children be respected during this stressful time."