A crew of four Whanganui firefighters responded to the call near Lismore Forest.
They were senior station officer Jason Hamlin, Carl Murphy, Shaan Stuart and Astrid Hartnell.
The crew, with help from the owners and neighbours, tied strops around Harley’s hind legs and began to pull.
“We managed to rock him until he broke the suction, and he did the rest himself, really,” Hamlin said.
“There were a couple of firefighters and one neighbour plunging round in the mud with it and gave it enough room to free one leg.”
He estimated the rescue took an hour from start to finish.
“The horse looked pretty tired when it came out.”
An exhausted Harley after he was freed from the mud pool.Hamlin has been a firefighter in Whanganui for more than 20 years.
He said he had only done a couple of similar rescue operations.
“It’s not your everyday run-of-the-mill stuff, I’ll give you that.”
In 2020, Whanganui firefighters rescued 14 ducklings that were trapped in a roadside drain.
Riddles said it was “very lucky” she saw Harley when she did because he might not have survived otherwise.
She has owned Harley for 16 years.
“[Harley] is my absolute heart horse, we’re very grateful.”
Her father, a vet, was present during the rescue had Harley needed any additional help.
Riddles’ mother, Joni Francine, said the rescue was “a real team effort” and their urgency was needed.
“[Harley] really is her soulmate; it really would have been heartbreaking for him to pass away in that way.”
“It’s not your everyday run-of-the-mill stuff," senior station officer Jason Hamlin said.The promptness shown by the fire crew was impressive, she said.
“It wasn’t a pleasant job because the bog hole Harley was stuck in smelled bad, deep, muddy and yuck.
“They just rolled their sleeves up, and it was beautiful; they didn’t hesitate to help us figure out a way to get him out.
“He’s a big horse, and you have to get up close and personal with him in that sort of situation, but they didn’t hesitate.
“They were potentially putting themselves at risk because a frightened animal can react unpredictably - they were great.”
Harley has now been moved to another paddock, and the mud pool has been fenced off.
“He’s good,” said Riddles.
Fin Ocheduszko Brown is a multimedia journalist based in Whanganui.