Much of NSW and parts of Queensland, South Australia, West Australia, the Northern Territory and ACT are predicted to cop soaring temperatures until Friday.

The first tropical cyclone of the season has formed in the Pacific, with meteorologists warning it’s expected to intensify and could move near the Queensland coast.

Tropical Cyclone Jasper is currently a slow-moving category one weather system about 1500 km northeast of Cairns, the Bureau of Meteorology says.

But it’s expected to strengthen and become a severe category three tropical cyclone on Wednesday as it tracks south-southwest towards the northeast Coral Sea.

“There is a potential for tropical cyclone Jasper to move near the Queensland coast next week (but) there is large uncertainty as to which parts of the Queensland coast will be impacted,” senior meteorologist Dean Narramore said on Tuesday.

“The bureau will issue regular updates to keep communities informed as the situation evolves over the coming days.”

Meteorologist Steven Hadley said some modelling suggested Jasper could travel south and cross the coast near Brisbane as a tropical low.

“But more likely than not, it would be in the tropical areas of Queensland … it’s just really too early to say just yet,” he told ABC radio.

The bureau’s technical bulletin said recent guidance favoured a scenario where Jasper approached the Queensland coast between Cooktown and Mackay next week.

“A small amount of guidance has a more southerly track, consequently moving the system towards the Queensland coast, south of Mackay,” it said.

NSW residents are in for a sweltering period with a severe heatwave warning issued from Wednesday which is expected to last for the next three days.

Residents in the northern tablelands, central west slopes and plains and lower and upper western districts are being warned by the Bureau of Meteorology about above average maximum temperatures, with some areas tipped to reach the high 30C to low 40C.

The Illawarra, Hunter and Riverina regions were also issued with a severe heatwave warning.

No total fire bans were declared but the NSW Rural Fire Service urged people in bushfire prone areas to have an action plan ready in the case of an emergency.

NSW Health also warned about the effects of heatwaves on vulnerable people, including those over 65 years, babies, young children, pregnant women and the homeless.

People are being urged to avoid being outdoors during the hottest part of the day, to wear sunscreen, sunglasses and hats and stay hydrated.

NSW Police reminded commuters to keep their cool on the roads, particularly if there were traffic delays.

“We know many people will want to head to the beach, a local swimming hole or swim in your backyard pool, please be careful,” a NSW Police spokesperson said.

“Keep a watchful eye over children especially when they are near the water, all children need to be supervised.”