A quick-thinking referee saved the life of a 14-year-old rugby player after he stopped breathing during a match.

Wellington College player Punaarika O'Sullivan - known as Puna - was hit hard in a tackle while playing in an under-15s match on Saturday at his home ground.

Aaron O'Sullivan - co-coach of the Wellington College team - said his son had just cleared the ball from his team's in-goal area and was running it out when he was tackled by a St Patrick's Silverstream player.

"He got clipped at the ankles ... and there was a big pile-up."

Puna's head hit a player's arm and shoulder on the way down and O'Sullivan knew his boy was out cold before he hit the ground.

"My assistant referee straight away said, 'He's out'."

A young referee named Monique Dalley, who happened to be on the sideline because she was refereeing the following game, saw the youngster was in trouble and ran on to the pitch.

With the match referee and two other people, Dalley began CPR because Puna had stopped breathing. She was also on the phone to emergency services getting advice.

"We all jumped in looking for a pulse and at that stage she said she couldn't get one, O'Sullivan said. "I heard from emergency services, 'Start CPR'."

Asked how long his son was not breathing, O'Sullivan said: "It felt like an eternity for me."

The ambulance arrived and worked on Puna for up to an hour. He eventually regained consciousness and was taken to Wellington Hospital before being discharged on Sunday.

O'Sullivan, a 36-year-old builder, said Dalley visited Puna in hospital, bringing him flowers and chocolates. He credits the young ref with saving the life of his son.

"I don't know how else to repay her. If she asks me to build her a fence I'll build a fence."

While Puna had suffered concussion, he was undeterred and raring to get back on the field with his team in three weeks.

"He's all ready to go," said his dad.

Punaarika O'Sullivan surrounded by family and friends in Wellington Hospital after being resuscitated at a rugby match in Wellington. Photo / Supplied

Dalley said she just did what anyone would have done.

"My instincts kicked in. I went over, saw a player on the ground and went down to assess what was happening and saw he was knocked out and just jumped into first aid mode.

"He was breathing not very well and it just got significantly worse to the point where he wasn't really breathing at all. It was pretty horrible."

Looking back, Dalley - who had only sat a first aid course the week prior - said it felt like a dream.

"I went in to check on him in hospital and he was like a completely different person - that was really cool to reconnect and see that he was all good."

Wellington Referees Association chairman Ian Dallas said the youngster was knocked out and had stopped breathing when Dalley and the others sprang into action.

"The four of them worked together, but particularly Monique, and effectively saved his life."

Dalley, who is in her 20s, is training to become a police officer, so first aid was fresh on her mind, Dallas said. And the match referee, who also assisted, was a qualified surf lifesaver.

"It's pretty special, we're pretty proud of [Dalley] particularly, but also the other three young guys," Dallas said.

"Young people responding like that is just absolutely fantastic."

Wellington College principal Gregor Fountain arrived at the school at the same time as the ambulance.

"He certainly wasn't breathing and what people said was it seemed to be for quite a long time that he had stopped breathing," Fountain said of Puna.

"By the time I arrived, they had just got into the ambulance and it was pretty emotional. There was a lot of relief, but there was still a lot of anxiety around the situation."

Puna's father was by his son's side.

Fountain said Dalley took control of the situation and after performing CPR and making sure Puna was okay went on to referee the 1st XV game.

"What we saw from these two - in particularly from Monique - was just extraordinary leadership. The ability to see a situation and take control of it and having used the skills you've got through your first aid training, through your police training to obviously take action saving someone."

Fountain was impressed that after finishing refereeing her game, Dalley emailed later that evening to see how Puna was.

Seeing how all the different teams and players had worked together had been a really uplifting community experience, he said.

Players from Wellington College's 1st XV team arrived as the situation was unfolding and pulled the younger team into their huddle and said a prayer for their schoolmate.

The 1st XV team also visited Puna in hospital.

The player, his parents and the Wellington College coaches thanked Dalley on Monday night. Puna was still sore but had mostly recovered.

Dalley is a level 2 Wellington rugby referee, meaning she officiates in top division Colts, First XV, and Premier Reserve senior club matches.

"A goal of mine is to referee a premier game in the future, which is something that a woman in Wellington has never done," she wrote earlier this year on the WRFU website.

"If I can continue to put the effort in off the field then hopefully I will get that opportunity."