Perth is looking at potential heatwave conditions for the first time since February 2016, with temperatures expected to hover close to 40 degrees Celsius from Wednesday to Sunday this week, on the heels of a record-breaking start to summer.

Key points: Perth's start to summer is already 7 degrees above the December average

Perth's start to summer is already 7 degrees above the December average Five days in a row are forecast to be above 38 degrees later this week

Five days in a row are forecast to be above 38 degrees later this week The hot weather will present tough conditions for the first NZ cricket Test

The Health Department said it was monitoring the forecast closely and would issue a warning by mid-week if the temperature met its threshold for a heatwave — three or more consecutive days when the forecast minimum and maximum temperatures average at least 32C.

Perth's maximum is tipped to range between 38 and 40 degrees from Wednesday and Sunday, while the minimum will range in the low- to mid-20s.

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The blistering heat comes on the back of Perth recording its hottest first week of summer on record, after the city's maximum averaged 36C — 7 degrees above the December mean maximum of 29.1C.

The last time the Heath Department declared an official heatwave was in February 2016, when Perth's maximum temperature surpassed 40C for four days in a row.

Heat is on for the first Test

The scorching temperatures will pose a challenge for the Australian cricket team as they coincide with the start of the first Test against New Zealand at Perth Stadium.

The forecast has prompted a warning from a doctor, Colin Hughes, who previously worked for the Western Australian Cricket Association (WACA) and the AFL.

Dr Hughes urged Cricket Australia to delay the day/night Test's start time of 1:00pm until late afternoon to avoid the worst of the midday heat.

Perth's December temperatures are currently 7 degrees above average. ( ABC News: Jon Sambell )

"There are huge health consequences to the players out in the middle — the heart can start racing and you can develop heat stroke through dehydration," he told ABC Radio Perth.

"That can apply to the spectators as well.

"If it's 40 degrees, you can imagine what the temperature would be like underneath a helmet in the middle of the pitch.

"I think that Cricket Australia just doesn't understand the implications of these incredibly high temperatures. There's a huge difference between playing in 35 degrees in Melbourne or Sydney and 42 degrees in Perth."

Dr Hughes questioned why it was appropriate to stop a Test match due to rain but not for heat.

"My warning to Cricket Australia — there is a cricketer or a spectator who is going to have severe problems if you allow that Test to start when the temperatures are still 42 degrees," he said.

"I urge them to delay the start of play, just as they would delay a start for rain, for about three hours until the temperature is below 35 degrees."

Delay? No way, says WACA boss

But WACA chief executive Christina Matthews rejected the idea of delaying the start, saying that "will never happen".

"It's always good to be aware of the challenges of hot weather, but in regards to the players, the players play all across the world in extreme temperatures and are very well prepared for it," she said.

"Cricket Australia will be monitoring the health of players as the game progresses."

The first Test at Perth Stadium is set to take place in scorching conditions. ( ABC News: Jarrod Lucas )

Cricket Australia caused controversy last year during a scorching second Test between Australia and India by choosing not to open the top tier of the stadium, which provides the most shade.

But Ms Matthews said that would not be an issue this week.

"Level 5 will be open this year, which is one of the most shaded areas in the ground, also there are lots of areas you can move back from the seating into areas that are not directly in the sun," she said.

"We'll also be having the red frogs people walking around spraying people who would like to get a little bit of relief."

Hot Tests nothing new: Warner

Test opener David Warner was unfazed by the forecast, pointing to several occasions when players have had to endure similar conditions.

"I go back to Bangladesh when Pete Handscomb and I were batting out there together, it was 31 degrees, but they actually said it was around 45 (on the ground) and come an hour into our innings, we were walking ones," he said.

"It was extremely hot and very difficult, we couldn't really get a lot of fluid into us.

David Warner celebrates a century during a previous Test against New Zealand in Perth. ( AAP: Richard Wainwright )

"I look back to an Ashes series we played [in Perth], it was 45 degrees. It was one of the hottest days I've ever played in Australia, and everyone was absolutely cooked.

"I remember that hurting a lot of us for the next couple of days afterwards."

He said players were accustomed to the heat and had preparation and recovery techniques in place to help them manage.

Perth weather forecast