The Bureau of Meteorology has issued either a severe or extreme heatwave warning for all forecast districts, with maximum temperatures in the low to mid-40's expected across much of the state until Friday.
A total fire ban has also been declared for the Wimmera, South West and Central forecast districts for tomorrow.
WorkSafe Acting Chief Health and Safety Officer Adam Watson said employers must be ready to adjust work arrangements to ensure workers are not exposed to serious health and safety risks.
"Employers have a legal duty to monitor workplace conditions and manage any risk to health and safety, including those created by extreme weather or natural events," Mr Watson said.
"This should include preparing a strategy tailored to each workplace and ensuring workers are educated on how to recognise fire risks and heat-related illnesses - both in themselves and others."
Working in high temperatures can lead to heat illnesses including dehydration, heat rash, heat cramps, and heat exhaustion.
Mr Watson warned if steps were not taken to hydrate, rest and cool down, heat illness could quickly progress to heat stroke, a life-threatening emergency requiring immediate medical attention.
"The best defence is to postpone outdoor work entirely or ensure it can be done safely during cooler parts of the day," he said.
"Employers should also take steps to limit physical exertion and fatigue, including for those working indoors, by encouraging workers to take regular breaks in a cool place."
Outdoor work that may provide an ignition source, such as welding and other hot works, must not performed in total fire ban areas.
To stay up-to-date with the latest information use the VicEmergency App or website.
