On Wednesday Christchurch soared to 32C as a spell of hot weather began to hit Canterbury and northern Otago.
Yesterday temperatures fell slightly beneath 30C but are expected back up to the stifling levels on Tuesday and Wednesday next week.
Fire and Emergency New Zealand also issued a public alert today reminding people stay hydrated, in the shade if possible, and take breaks when travelling.
"Often with warmer temperatures, people get really tired and fatigued quite easily, so if you're driving make sure you take rest breaks and take care of yourself," acting national rural operation manager Mr Mitchell says.
Homeowners should also not overload power sockets as fans are purchased in high numbers, he said.
Multiple Sclerosis NZ's website says: "Many people with MS become quite sensitive to the heat, particularly during the summer.
"An elevated core body temperature, of as small as 0.5degrees, (whether from illness, heat, or activity) can alter the effective conduction of nerve impulses. This can result in a feeling of fatigue, as well as a temporary worsening of other symptoms."
It's important that those with the condition avoid becoming over-heated by "keeping the body cool with the liberal use of air conditioning, wearing cooling garments (specially designed to lower body temperature) or other cooling strategies may help to manage heat sensitivity and resulting symptoms.
"Symptoms will usually subside once nerves are returned to normal temperatures."
How to avoid over-heating
Water/nutrition:
• Increase fluid intake (but not coffee, which dehydrates)
• Sucking ice cubes is good for cooling down
Clothing:
• Put some frozen veggies (still in the bag), wrapped in a tea towel around your neck or try freezing a bandana, scarf or tea towel
• Wear a wide-brimmed hat outside
• When you put your fan on put a damp towel around your shoulders to cool down quicker
