The dog also has extensive bruising to her internal lower abdomen, indicating being punched or kicked, SPCA said in a statement.
The dog had no identification tags and was not registered. In a statement SPCA said it has made extensive efforts to try and find further information about the dog, and was now appealing to the public for witnesses and information.
"We are extremely saddened and horrified about the way this dog spent her last moments alive," Jones said.
"She would have been incredibly frightened and in pain. We are urging anyone with information on this dog to come forward. The park is well-used and has registered about 24,000 users a year, including dog walkers, runners and mountain bikers."
SPCA urges anyone with information to contact Rotorua SPCA on (07) 349 2955, quoting job number SB366725.