New Zealand heatwave: Weather at 'dangerous' level, concerns about national emergency

While the hot weather currently bearing down on New Zealand may be appealing to beachgoers, a medical expert is warning the heat is at a dangerous level and there are concerns about a national emergency.

On Monday, temperatures soared pass 30degC, hitting a high of 37degC in the Hawke's Bay and 36degC in the Marlborough Sounds, prompting warnings from meteorologists and district health boards for the public to keep hydrated.

Tuesday is expected to be another scorcher, with inland areas across the North Island expected to bear the full brunt of the hot weather, according to WeatherWatch.

In the South Island, Marlborough, Nelson, the West Coast, Southland and Otago may also reach 30degC.

Canterbury District Health Board medical officer Alistair Humphrey said Kiwis should not be complacent, saying the weather is at an extremely dangerous level that may be closing in on being a national emergency.

He said elderly and young children were particularly vulnerable, and Kiwis should make sure they are stocked up on fluids all day long and keep the windows open.

"Elderly people, who don't regulate heat quite as well, [are coming into emergency departments] dizzy, not having drunk enough, not having being wearing a hat," he told The AM Show.

Mr Humphrey said that all heat waves are dangerous and can lead to dizziness and confusion.

"Every emergency department, every hospital, has its own plan for excess casualties coming in for whatever cause... [but] we are hoping people heed the warnings".

On Monday, he warned that drinking too much alcohol during warm temperatures can lead to heatstroke.

Alcohol interferes with the regulation of water levels in the human body, causing you to urinate more. As your body runs out of water, dehydration may set in, causing headaches, dizziness and confusion.

"If someone's not wearing a hat and they're in the sun, or if you think someone's not drunk enough water - or, in particular, if you think they've had too much alcohol, because that will also dry you out - I think a bit of friendly advice can often stop someone from ending up in the emergency department," said Mr Humphrey.