"I went to see what was happening and (name deleted) was mediating as he knew some of the people from the uninvited group. He was trying to get them to leave. While I was standing by someone punched me in the face.
"I fell over and was bleeding badly from my face... I had a significant cut to my upper lip," said the Year 13 student, who was taken to Thames Hospital and later to Waikato Hospital to get his lip repaired by a plastic surgeon.
His mother said her son was unable to eat for six days and was left with permanent scarring.
The teenager's mother - the Herald has agreed not to name the mother and son - came forward after a similar story in the Herald on Sunday about a father's anger that police had not arrested two teenagers who allegedly beat his son beyond recognition.
At a birthday party last month in West Auckland, the boy was allegedly set upon by two teens who he knew from school, as he went to leave.
The teenager suffered critical injuries to his head and narrowly avoided brain damage. His eyes were so swollen they had to be prised open. The Year 11 student was in hospital for a week and is recovering from a severe concussion.
The father said as far as the Henderson police are concerned, his son could be dead.
"A box in the ears, a black eye, and a bloody nose is one thing, but kicking someone's head is unacceptable. What does it take before anything gets done?" said the father, who received a text from a police officer saying she was now assigned to the case after the Herald on Sunday made inquiries.
The mother of the boy who suffered serious injuries from the king hit said she notified the police on June 27 of the name of the alleged offender, and two weeks later the file has not been allocated to an officer and the police stopped answering her questions.
She said the police officer who took her son's statement said it was the worst injury he had seen and that one punch could be fatal. The officer said the alleged offender would appear before a community board at worst, she said.
"Good kids are having adverse and life-changing events through no fault of their own and as parents we need to be more alert to the violent culture among youth and the lack of consequences for the same.
"We are professional educated parents and the system has failed our son. I think the public needs to know the reality as we have experienced every parent's worst nightmare," said the mother, who wants the police to bring criminal charges.
A police spokesperson said they received a call at about 1.25am on June 25 following the report of an assault where the victim was taken to hospital to receive treatment for a lip injury.
Following initial interviews and investigation, it was decided on July 7 that the file would be referred for further investigation. The file was reviewed on July 11 and assigned to an officer in charge on July 14, the spokesperson said.
"At this stage, there have been no witnesses willing to give statements to police, and the victim has also not signed a statement. Police will continue to investigate any available lines of inquiry," said the spokesperson.