Dr Shirley Lyford Tonkin, a prominent paediatrician and founder of the Cot Death Association, died peacefully at her Auckland home on Wednesday.
She was an advocate for child safety and one of three researchers involved in the development of a foam insert for car seats which helped prevent babies from choking.
The foam insert helps keep the babies' heads upright in a natural position instead of slumping forward.
Margret Free, chief executive of Sids and Kids New Zealand, an organisation raising awareness about sudden infant death syndrome, said Dr Tonkin was the person responsible for renaming cot deaths as Sids.
She said the amount of work Dr Tonkin put into the cause was "absolutely endless".