The NRU "along with the New Zealand Rugby Union and the Rugby Foundation are currently working with all parties to support the family through this tough time.
This is a tragedy for all concerned, in particular Jordan's immediate whanau and friends," the statement said.
"The NRU are currently working through the serious injury investigation process and will forward this through the appropriate parties investigating his death.
"Jordan was a young man with a passion for life and for rugby, he was a great guy from an awesome family and will be sadly missed by all who knew him.
"Counselling for his fellow club members has been arranged. This counselling is also available to anyone who requires it by contacting Greg Shipton at the NRU. All contacts are confidential."
Jordan Kemp, 17, had been back playing for five weeks after a serious head injury at the start of the season.
It is understood Kemp was being monitored for a brain bleed.
He is the grandson of Russell Kemp, a prominent rugby coach and Maori leader from Kaiwaka.
Otamatea club president Kevin Robinson was at the game and said Kemp went to the ground after the hit but then got to his feet.
"He fell down but then got up and staggered around before falling over again," Robinson said.
"He was looked after immediately and the game was called off."
In February Northland Rugby implemented a "blue-card" system giving referees the ability to order concussed players from the field for a minimum of three weeks.
Kemp had been blue-carded at the start of the season, had four weeks off and had been cleared five weeks ago.
Robinson was with Kemp the first time he was knocked out with a knee to the head.
"That was awful. It was not nice to see," Robinson said. However, he didn't think Kemp was cleared too early and said the teen had made a full recovery.
"He was being considered for the Northland under-18s, he was doing really well," Robinson said.
Jordan's coach, former All Black Dean Kenny told 3 News rugby was Jordan's passion.
"Just last week ... it was raining cats and dogs and he turned up with his bare feet and he was just running around, kicking the ball around, and he just loved the footy."
After the tackle that resulted in a knee to Jordan's head, he started stumbling about, bumping into players, Kenny said.
"And then he just collapsed."
Kenny said there needed to be better systems in place for players who had suffered a concussion.
"Why don't we have a look at having a hotline and somebody is there all the time for coaches for GPs to phone up and just ask?"
New Zealand Rugby Union chief executive Steve Tew was concerned to hear of Kemp's injuries.
"We will get an accident report and respond as we always do but I will try and find out what has happened to him now," Tew said last night.
Warriors doctor John Mayhew said there was no set stand-down time for head injuries.
"Some players need a few days, some need three years," he said.
Mayhew said clinical assessments and neurological tests were needed to assess when a player could return to play.
"I would hope the people who cleared him to play made the right clinical assessment.
"Three or four weeks is probably appropriate for most head injuries to recover. But there are exceptions to that."
