Tooth, 25, a former agricultural economics student at Sydney University, collapsed after making a tackle while playing against the Narrabri Blue Boars at Quirindi Rugby Park in the Liverpool Plains town.

Tooth, who lived in Sydney, received emergency medical attention at the ground and was then flown to John Hunter Hospital in Newcastle, but died late on Sunday.

The Central North Rugby Union immediately offered its thoughts and full support to the Tooth family, the Quirindi Lions club and the Quirindi community.

On Monday morning, the Australian Rugby Union chief executive Bill Pulver said in a statement: "The passing of one of our young country rugby players over the weekend is incredibly sad and is a loss that is felt by the entire Australian rugby community.

"We send our thoughts and sincere condolences to Nick's family, friends, teammates and members of the Quirindi rugby and broader community.

"I'd like to thank those who helped at the scene on Saturday and we'll ensure we provide whatever support we can for Nick's family and club at this challenging time."

The NSW Rugby Union also declared its support, with NSW Rugby Union chairman Nick Farr-Jones saying in a statement: "On behalf of the NSW Rugby community, I would like to offer our sincere condolences and support to the family and friends of Nick Tooth, and to the rugby community of Quirindi and the Central North region.

"We will be providing ongoing assistance to Nick's family and rugby club during this difficult time."

Last year the Sydney rugby community was rocked by the death of Balmain player Toby Crisp who suffered a heart attack during a match.

The 25-year-old was rushed to Royal Prince Alfred Hospital where he underwent emergency open heart surgery to try and repair a valve in his heart but he passed away a week later. 
Terry Woodward the executive officer of the NSW Country Rugby Union described Tooth's death as a tragedy and lamented it wasn't the first game-related one he'd dealt with.

"This is unfortunately not the first time I have been involved in this situation, I've had two or three since I've been in this job," he said. "Our main objective is to provide support to the player's family, the club, the club's players,  the team they played against and the match officials.
"That will be in the form of counselling and any other assistance we can do to try and help them.

"Our main objective is to provide support. The ARU has a crisis manager who specialises in these kind of instances.
"This has been a tragic accident. There was no malice, it was a tackle that went wrong. It's rocked the rugby community just as the Phillip Hughes tragedy did cricket."

On Monday morning, the Quirindi Lions club posted a message on its Facebook page: "The Quirindi Rugby club would like to send their deepest condolences to the Tooth family on the loss of Nick.

"The loss of this kind hearted and fine young man will be felt far and wide.

"The club would like to offer their support to everyone who has been touched by this tragic loss ... The players and club members thank everyone for their thoughts and support at this sad time."

Waratahs back-rower Pat McCutcheon, who knew Tooth, said the Super Rugby champions felt for Tooth, his family and the Quirindi rugby community.

"I came across him a few times," said McCutcheon, who is registered with the Sydney University club.

"That's obviously a devastating thing to happen in Quirindi rugby, for the Lions and let alone the rugby community.

"I hear Nick was a fabulous kid. It is [so] tragic for the family and the community up there in Quirindi.  As the Waratahs, we send out our love and support.  We are always there and it is times like this when the rugby community really binds together and shows our strength."

According to an ABC report on Monday morning, Tooth, also a former student from the Sydney Church of England Grammar School (SHORE) in North Sydney and originally from Wallabadah in New England region of NSW, the incident is not being treated as suspicious and a report was being prepared for the coroner.

Quirindi Lions club president, Charles Murray told the ABC Radio's Kelly Fuller that Tooth was visiting his home town from Sydney for the weekend.

"It was just a very tragic accident," Murray told ABC.

Murray told ABC that there was "nothing untoward" in the tackle that injured Tooth.

"It really was just a tragic accident, Nick went in to tackle an opponent and his head clashed with [the opponent's] shoulder and he went down," Murray said.

"There was no foul play, nothing untoward about it at all; sadly it was just a very tragic accident."

Murray also reflected on Tooth's rise within the agricultural grain industry: "I'd seen him grow up from a child through junior rugby and grow into a young man, he was a lovely kid, he had a bit of a larrikin spirit in him.

"He was a really good bloke and very popular, and his family for generations have been great rugby supporters in this district and great community people."

Murray said the ARU support and offer of counselling were welcomed.

"It's imperative that we keep them together and we keep them talking about it, and they get it out in the open rather than bottle it up," he said.