There's a plea for more Victorians to get vaccinated against Japanese encephalitis this summer with the jab available for free in regional areas.

The disease is transmitted by mosquitoes and most people do not become sick but symptoms can include a fever, vomiting and headaches.

In more severe cases patients can experience seizures, paralysis, permanent disability or even death.

There are 20 local government areas in regional parts of the state considered high risk this year, particularly for those who spend time outdoors.

The jab is available free of charge for anyone who lives or works in Benalla, Buloke, Campaspe, Gannawarra, Greater Bendigo, Greater Shepparton, Hindmarsh, Horsham, Indigo, Loddon, Mildura, Moira, Northern Grampians, Strathbogie, Swan Hill, Towong, Wangaratta, West Wimmera, Wodonga and Yarriambiack.

Vaccines will be administered at GP clinics, Aboriginal community-controlled organisations, community pharmacies and local councils.

The Victorian Health Department says the risk of infection increases in the warmer months from November to March due to a higher number of mosquitoes.

There was just one recorded case in the state last season but earlier this year health authorities revealed the virus had likely infected more people than previously thought.

Blood samples showed an estimated one in 30 in affected northern Victorian council areas might have contracted the virus.

The federal health department says 45 cases were detected across the country between January 2021 and December 2022 with seven deaths.

Mosquito-borne diseases have been on the rise in flood-affected areas in southeastern Australia

This year three Victorians died from the Murray Valley encephalitis virus, but there is no vaccine to protect against that disease.