The state's Deputy Chief Health Officer Deborah Friedman issued a warning on Wednesday about the Murray Valley encephalitis virus, saying there have been more detections in mosquitoes trapped at multiple locations across Victoria's north.

The results meant the virus was circulating widely in the mosquito population and there was a "significant risk" to people in the affected areas - particularly in Mildura and northern Victoria's inland river regions.

"The risk area for (the) virus is similar to that for Japanese encephalitis virus and the risk of human cases in the coming weeks is very high," Associate Professor Friedman said.

"This risk is expected to continue while mosquito numbers remain elevated."

The virus is a rare but potentially serious disease that can cause permanent neurological disease or death, but is generally mild or not severe enough to cause symptoms.

The deputy chief health officer urged residents and visitors of Victoria's north to reduce their risk of mosquito bites by covering up, wearing repellent and avoiding being outdoors at dusk and dawn.

Event organisers had to consider their obligations to keep people safe, Ass Prof Friedman said.

Health authorities on Saturday warned of the risk both the Murray Valley encephalitis virus and the West Nile/Kunjin virus pose.

Australian Associated Press