A child injury prevention service says at least 20 children end up in hospital each year after swallowing button-shaped batteries and it wants manufacturers to change battery design.
The batteries are under scrutiny in Australia where a four-year-old girl died after swallowing one.
The child was taken to Queensland's Noosa Hospital on 30 June with stomach bleeding and could not be saved.
SafeKids director Ann Weaver says the lithium batteries can start burning through soft tissue in about two hours.
Ms Weaver says battery manufacturers in New Zealand are about to launch new packaging that's more difficult for children to get into.
But she says SafeKids is also pushing for the companies to make changes to the design of the batteries themselves.
Ms Weaver says the organisation is also trying to raise awareness among parents and medical workers of what to do if a child swallows a button battery.