Fire and Emergency New Zealand risk reduction adviser Scott Lanauze said lithium ion batteries had become popular because they provided high, consistent rates of discharge in a small package.
The batteries were used in phones, laptops, tablets and power tools, through to electric vehicles.
Many plug-in electronics with standby switches, such as TVs, had them, as did most solar-powered buildings.
But incorrect charging and maintenance of the batteries could have serious consequences if they caught fire in a process known as thermal runaway, Mr Lanauze said.
Thermal runaway happened as a result of damage to the tiny cells which made up a battery.
A chemical reaction took place, releasing heat which could lead to toxic fumes, flames and explosions.
One way electrical damage could be caused was by using the wrong charging equipment.
"I don’t think there’s any need to be to be worried about this, provided that the equipment that is being purchased and being procured for use is being looked after as per what would generally be the standard," Mr Lanauze said.
He encouraged consumers to follow the manufacturer’s directions for charging and storing their devices.
In the event of a fire due to thermal runaway, water could make it worse, he said.
While a fire extinguisher might help, Mr Lanauze recommended calling 111.
"We’ll come along and we’ll deal with it because you don’t want to end up breathing in that smoke. You’ll end up pretty sick," he said.
