They departed on Monday morning and will return to New Zealand on February 2.
Victoria is experiencing extreme weather conditions with multiple bushfires, which have killed one person and caused extensive damage to homes, property and the environment.
Emergency Management Victoria formally requested help from FENZ last week.
FENZ said the contingent being sent consists of 20 firefighters experienced in arduous conditions, and two liaison officers.
One of the crews is from the Department of Conservation, one is from the forestry industry and the other two crews comprise volunteer firefighters from FENZ brigades around the country.
Assistant National Commander Ken Cooper said the firefighters' tasks would be confirmed when they reach Melbourne, but they are equipped and ready to stay at a fire camp in a remote location.
Fire and Emergency has international agreements to provide mutual assistance, and regularly deploys personnel overseas to Australia, Pacific Islands and North America.
"We assess each request to ensure that we have the capacity to send appropriate personnel without compromising our ability to maintain full capability to respond to incidents at home," Cooper said.
