Victoria Police officers are in isolation after rescuing a man who is believed to have jumped from an oil tanker in Melbourne.

The 31-year-old Georgian national was rescued in Port Phillip Bay on Sunday night, about five kilometres from where the international tanker had docked.

The man is expected to be transferred to mandatory quarantine once he is released from hospital.

The police air wing found the man clinging to a navigational marker.

The water police officers who rescued the man then went into isolation as a precaution.

Victoria Police would not disclose how many officers are isolating, citing operational reasons.

Victoria has gone 74 days without a local infection, with one new case in hotel quarantine.

There were 8155 vaccine doses and 12,918 tests in the 24 hours to Tuesday.

-AAP