SAFE (Save Animals From Exploitation) said Rapido Scud died on Friday after a race at Hatrick Raceway in Whanganui.
The dog collapsed at the lure and was pronounced dead upon returning to the kennel block.
An autopsy to determine the cause of death was still pending, but campaign manager Emma Brodie said it was not an isolated incident.
"This heart-wrenching incident follows closely on the heels of the deaths of two other dogs, Jovita and Palawa Queen, who suffered catastrophic fractures at Addington Raceway in Christchurch just eight days prior and had to be euthanised," she said.
"In fact, since the greyhound racing industry was formally put on notice on 2 September 2021 for repeated animal welfare failings, there have been 2529 injuries, 268 fractures, and 25 deaths."
In March, three dogs died in one week and racing was suspended for five weeks at Manukau Stadium by Greyhound Racing New Zealand (GRNZ) because of a "concerning increase in injuries".
The day before the latest death, the Racing Integrity Board fined trainer Jack Johnson $1000 and suspended him from racing for 12 months after his greyhound Big Time Heaven was found to have unsafe levels of arsenic in her urine following a race at Christchurch's Addington Raceway on 11 March.
The arsenic was attributed to her ingestion of significant amounts of plywood housing. Arsenic exposure is linked to serious health issues in dogs, including cardiovascular problems, vomiting, diarrhoea, lethargy, and even death.
"It is deeply upsetting that dogs continue to suffer catastrophic welfare outcomes while we await the Government's decision on the future of the industry," Brodie said.
"We urge Racing Minister Winston Peters to take decisive action and call time on greyhound racing in Aotearoa to protect these gentle animals from any further harm.
"Furthermore, the recent charges against Jack Johnson demonstrate that even outside of racing, greyhounds in this industry are subjected to neglect and confinement in harmful conditions."
SAFE pointed to a recent poll commissioned by the SPCA, which found 74 percent of New Zealanders would vote to ban greyhound racing in a referendum.
