While the temperatures have cooled after last week's scorcher, the mercury is expected to rise again, with 35 predicted for Melbourne on Friday and 39 across the weekend.

Emergency Management Commissioner Craig Lapsley said there were more than 80 grass and scrub fires last week alone and Victoria's fire risk remains high this weekend.

"This long weekend will combine extreme heat, significant fuel load and thousands of Victorians in transit as they travel either to Australia Day events or come home from summer holidays," Mr Lapsley said.

"We saw over 80 grass and scrub fires last week and those conditions will have dried fuel-loads even further. Communities need to be aware of the conditions, take shelter in the heat of the day, make sure they stay hydrated and check local conditions."

Several people died from cardiac arrests as searing swept across the state last week as temperatures hovered above 40 degrees.

Paramedics were called to 31 cardiac arrests last Thursday, with a number of people dying.

Mr Lapsley urged people to check on vulnerable friends and family members who may be elderly or have pre-existing health problems, as emergency services plan to roster on more paramedics for the weekend.

Melbourne hospitals, including The Alfred, enacted a 'Code Yellow' last Thursday and switched off non-essential lights and equipment to conserve energy amid last week's searing heat.

It is likely the Health Department will again tell Melbourne's hospitals to prepare their emergency plans in the case of power outages due to the hot weather.

Relative humidity has been between 90 to 100 per cent overnight, as a tropical air mass makes the state more suitable for saunas than sleeping.

The humidity will drop slightly on Monday and Tuesday nights, before heading back into the uncomfortable zone.

Weather conditions conspired to pull a tropical air mass over the state last week and a slow-moving weather pattern is ensuring it sticks around.

It's a pattern we see every summer, but Melburnians more accustomed to dry heat are ill-equipped to cope with the kind of humidity normally reserved for northern NSW.

"Normally in Melbourne you do get a cooler night," said Richard Carlyon, senior forecaster at the Bureau of Meteorology.

"It's not an easy one to escape and our bodies haven't really acclimatised."

But if you're feeling the heat here, spare a thought for our northern neighbours, who haven't felt the coastal cool change.

Bendigo is facing its fifth consecutive day above 35 but the forecast suggests the city may suffer through 11 or 12 days at those temperatures.

"Bendigo got 37.9 degrees today [Monday] and it's going to stay around that area for the next two days and head into the 40s approaching the weekend," Mr Carlyon said.

"Early next week there will be some cooler air or milder air moving in from the south, that will start to knock the temperatures down to 35 [next] Monday."

In Mildura, the forecast "cool" day is Monday at 37 degrees. From there, temperatures are predicted to creep steadily upwards before hitting a forecast high of 44 on Sunday.