Agriculture Victoria is urging producers to be vigilant for fly strike after the recent heavy rainfall and floods.
Significant fly issues have already been noted in some regions, and the timing and level of future high concentrations of flys may vary across the state.
Agriculture Victoria Senior Veterinary Officer Robert Suter said regular inspections of all mobs is vital.
"In Victoria, scouring and dags are the major risk factors for breech strike and there have been a large number of reports of dirty sheep this spring," Dr Suter said.
"Simple management tools to help prevent breech strike include controlling worm burdens by monitoring faecal egg counts and drenching as needed."
"Crutching and timely shearing can also significantly reduce the likelihood of strike, ideally crutching prior to flies becoming a problem."
Body strike is most likely to occur when sheep have fleece rot or dermatitis (also called lumpy wool or dermo).