Fau Vake (25) was injured in Symonds St during a brawl which erupted about 3am last Sunday.
"It is with inexplicable sadness almost seven days to the hour after his hospital admission, Fau's fight to find his way back to us ended," a statement from City Kickboxing said today.
"At this tragic time, the Vake family and City Kickboxing ask for time to grieve and reflect on the loss of Fau, a father, a son and a much loved brother to us all.
"We will speak when the time is right to ensure Fau's loss is not forgotten, but for now please respect our privacy."
The family of Vake had been asking that he be kept on life support as they prayed for a miracle.
Vake had been in a critical condition in Auckland Hospital.
A family member told Tongan news site Kaniva News that the family had asked doctors to keep their son and brother on life support as friends and family uplifted him in prayer.
Vake's mother was staying positive and wanted more time while they prayed for their boy, the publication reported earlier.
City Kickboxing head coach and friend Eugene Bareman earlier said the situation was "pretty dire" and that doctors had been gracious enough to tell it like it is.
"He's hanging on by a thread. So yeah, we're praying for a miracle. That's what we need at this stage."
Vake, father to a 3-year-old girl, was critically hurt in the incident on Symonds St early last Sunday.
Four men have since been charged in relation to the incident and appeared in the Auckland District Court on Monday.
One is charged with common assault, another with two counts of assaulting with intent to injure, another charged with wounding with intent and injuring with intent and another is also charged with common assault.
Three of the men are all aged 29. The fourth is a 32-year-old.
Earlier, family spokesman Mike Angove told the Herald that Vake's young daughter was staying by her dad's bedside.
More than 100 people had come through to visit the young man over the past few days, Angove said.
Some of MMA, kickboxing and boxing's biggest names had also come together to support Vake - including MMA champ Israel Adesanya, professional boxer Junior Fa and MMA athlete Mark Hunt.
Bareman said earlier that the Vake family was very much a part of their gym, as he is one of four brothers involved in MMA and linked to the gym.
He said out of the four, Vake was the one earmarked to go far in the sport.
Bareman revealed that on Saturday, hours before the incident that left him hurt, Vake had been sparring with Adesanya - and that it was Vake who got the better of the MMA champ.
