This week's temperatures have lived up to expectations. Following a hot 39.4 degrees Celsius Monday, Stawell recorded a stifling 44 Tuesday and 42.5 Wednesday. 

Overnight temperatures in the mid-20s have also made for an uncomfortable night's sleep. 

Ambulance Victoria paramedics are warning people to look after themselves and elderly or frail relatives and neighbours as the heatwave intensifies.

The heatwave is now the worst since the lead up to the 2009 Black Saturday fires.

Ambulance Victoria’s Manager of Emergency Management Paul Holman said tragically the 2009 heat claimed a large number lives.

"The hot weather including high overnight temperatures in 2009 led to an extra 374 deaths across Victoria in a week," Mr Holman said.

"People under-estimate the impact the heat can have and need to respect the weather.

"We’d urge the community to act responsibly to minimise the impact of the heat and to also check on elderly and frail relatives and neighbours to make sure they are okay.

"Avoid exercising or spending long periods outside in the heat of the day."

Ambulance Victoria has activated its emergency response plan to the second highest level to cope with any increase in calls. All available resources across the state will be deployed to respond to the extra demand.

Mr Holman urged people to consider other options if it’s not a life threatening emergency.

"If you are suffering chest pain or any other serious medical condition, then certainly call triple zero. However if it is something less urgent then just think about whether a doctor, Nurse On Call, a relative or some other service is more appropriate," he said.

‘It’s also important that people who call an ambulance respect paramedics, who face a difficult job working in the heat and we thank our staff for their efforts."

Fire crews have also been kept busy battling several blazes ignited by lightning strikes over the last couple of nights.