Victorians still not getting heat message

Victorians still aren't getting the message about heat safety, the chief health officer says, as the state prepares for another wave of scorching weather.

With temperatures set to top 40 degrees across much of the state on Sunday, Victoria's chief health officer Rosemary Lester said it was taking time to get the heat safety message across.

"The recognition of heat as a significant public health issue has only come about in the last five years," Dr Lester said on Friday.

"You don't change community attitudes overnight and this is the first serious incident we've had since 2009."

Paramedics attended more than 400 cases of heat exhaustion in mid-January as Melbourne had a record run of four consecutive days above 41C.

Ambulance Victoria escalated its emergency response plan to orange on Thursday, its second-highest rating, in preparation for the weekend's weather.

Ambulance Victoria operations manager Paul Holman said some outdoor events, including the Laneway Festival, had requested extra paramedics.

An extra 126 ambulance shifts have been rostered for the weekend, while the Emergency Service Centre will be in operation.

Heat health alerts have been issued for seven out of nine Victorian districts for Saturday and Sunday, with only the Gippsland region escaping a warning.