A coroner's inquest was told Natasha Harris, a 30-year-old mother of eight from Invercargill in southern New Zealand who died in February 2010, drank huge amounts of the caffeinated beverage, Fairfax Media reported.
It said pathologist Dan Mornin told the inquest that he believed Harris died from cardiac arrhythmia and was also suffering from low potassium levels and caffeine toxicity.
Mornin testified her excessive soft drink consumption probably contributed to her medical condition, along with poor nutrition, Fairfax reported.
Harris' partner Christopher Hodgkinson said she was addicted to Coke and the dead woman's mother-in-law Vivien Hodgkinson had called for soft drinks to carry health warnings, Radio New Zealand reported.
"The first thing she would do in the morning was to have a drink of Coke beside her bed and the last thing she would do at night was to have a drink of Coke... she was addicted to Coke," Christopher Hodgkinson said.
Vivien Hodgkinson said her daughter-in-law would "go crazy if she ran out... she would get shakes, withdrawal symptoms, be angry, on edge and snappy".
"We never knew it was any harm because it was soft drink with no warning labels, I've never seen her drink anything else the fridge was always full of Coke," she said. "Maybe it needs warning signs."
Coca-Cola Oceania told Fairfax that excessive consumption of any liquid, including water, could have health impacts.
"We concur with the information shared by the coroner's office that the grossly excessive ingestion of any food product, including water, over a short period of time with the inadequate consumption of essential nutrients, and the failure to seek appropriate medical intervention when needed, can be dramatically symptomatic," it said.
The corner is yet to hand down findings in the case.

I MUST WARN TO STOP MY SELF TO DRINK SO MUCH AYT?!