When a child swallows a battery, it's a race against the clock to diagnose and remove the device before it breaks down inside the body within two hours.
Every year, about 20 children are injured so severely after swallowing batteries that they're admitted to Starship hospital.
Health professionals have renewed warnings to parents about the dangers of batteries after the death of a 4-year-old girl in Queensland who suffered stomach bleeding from swallowing a lithium battery.
"Get children to a hospital as quickly as possible and let the doctors know they could have swallowed a battery. Insist that they investigate," said Ann Weaver, Safe Kids New Zealand director.
"We don't have the luxury of waiting for it to pass because it's a two-hour timeframe before it actually starts to cause damage."