Firefighters used power tools to free a woman impaled in the thigh by two metal spears on church fence this morning.

Emergency services were called to Pitt St in the central city about 5.15am after the woman became stuck on a fence at Pitt Street Methodist Church.

Fire Service senior station officer Sulu Devoe said the woman was in "real agony" when he arrived and was being supported by her partner, who was standing in the church grounds supporting her weight.

He said there was no way the woman could have freed herself, even with her partner's help.

The palings were lodged about 5cm to 7cm into her right leg.

"The spikes had gone in right on the top of her thigh, in the crotch area... she must have got one leg over the fence and then slipped and her weight has thrown her onto the spikes," Devoe said.

"She was in great pain and was going into shock."  

The woman, believed to be in her 20, was given pain relief before fire and ambulance staff helped to support her weight while others used a small disk cutter and a hydraulic cutter to free her.

Because the palings were close together, cutting her free was "quite difficult" and took the fire crew about 30 minutes.

Water was used to cool the cutting tools and prevent the metal spikes from heating up and burning the woman.

"She was in an awkward position and because the palings were so jammed up, so close together, cutting them was difficult," Devoe said.

He wasn't sure if both palings were removed from the woman's leg before she was taken to Auckland City Hospital.

"One or two were still attached to her... definitely one of them."

Devoe said he wasn't sure what the couple were doing at the church, or if they were intoxicated.

No trespassing signs were visible, he said.

A hospital spokesman said the woman suffered two puncture wounds and was treated at the emergency department.

He said the woman's injuries were "pretty minor" and she was in a stable condition.

The woman was expected to be discharged from the hospital later today.

The Fire Service had left the scene by 6am.

Police did not attend the incident and the church could not yet be reached for comment.

- © Fairfax NZ News