The youngster, along with two others aged six and 11, were reported to the health department several weeks ago, acting Chief Health Officer Angie Bone confirmed on Tuesday.

The majority of cases were aged-care residents, but there could be others who have died from the flu who had other conditions as the department is not notified of all deaths, she said.

So far 10,683 confirmed flu cases have been reported since the current season started late last year, Dr Bone said.

"It's certainly not showing any signs of tapering off, but it's not showing any signs of suddenly taking off with a massive increase," she told 3AW radio of the flu season.

Health Minister Jenny Mikakos blamed the early season on people travelling when the flu is at its peak in the northern hemisphere.

"We are seeing a lot of communicable diseases spread through overseas travel, that's certainly been the case in terms of measles cases and flu cases," Ms Mikakos told reporters.

"We have seen a very significant summer flu season this year as a result of people coming back from the northern hemisphere with the flu and that spreading in the community."

Ms Mikakos said the death of three children was unusual.

"(Juvenile flu deaths) do tend to be associated with situations where there might be other illnesses and vulnerabilities involved with those children," she said.

Authorities are urging Victorians to get a flu vaccine.

The federal government has a program of flu vaccines for vulnerable people, expanded by the the state government, making it free for children under five years old.

"We have put in an order for a record number of flu vaccines this year, two million flu vaccines for Victorians are available," Ms Mikakos said.

Australian Associated Press