Teenagers dressing in emerald and calling themselves the "green gang" have threatened high school students in East Auckland and told a mother her son was going to die.
Most recently, a small group of the youths waited with wrenches hidden up their sleeves for a Pakuranga College student to leave school. However, the girl was intercepted by another student and taken to school officials who notified the community constable.
About two weeks ago, a mother of a different student at the school said about 15 teenagers all with their faces covered in green bandannas turned up to her home about 7.40pm asking for her eldest son, who is 14 years old.
Her husband answered the door and told the four youths, they believed aged between 14 and 16-years-old, standing on their doorstep to remove their masks, but they refused. One of the teenagers was known to the family as he used to be friends with their son - the husband took him aside and told them to leave the property.
As the group dispersed, one girl yelled: "[Your son] going to die tonight."
The woman told the Herald she had contacted one of the teenagers' mothers to tell her what her son was involved in.
"They're just kids who are up to no good."
The threat against her son's life followed months of harassment, the woman said.
"He couldn't ride his bike outside in broad daylight, he couldn't even walk down to the dairy. We've had numerous times where he'd be walking somewhere and phone and say, 'Mum, you need to come get me, they're out'."
The woman believed her son and the member of the "green gang" fell out after he refused to join the group.
This week, a group of girls in green bandannas waited for a Pakuranga College student with wrenches up their sleeves after school.
"That it's gotten to that level, that's really concerning for me because my son is known to them. I don't need to be sat at work panicking every day and wondering if he's going to be targeted before or after school," the mother said.
Chairman of the board of trustees at Pakuranga College, Trevor Middleton, said there had been multiple instances involving the "green gang" this year which had been referred to the police.
However, he said they involved a small number of individuals and the school was aware of who they were.
"Is there a concern? Yes, there's always a concern when things like this happen. But is it an immediate threat? I'm not sure it is."
Mr Middleton praised the actions of the students who alerted school officials.
However, police spokeswoman Shelley Nahr said there had been no complaints to police over the alleged incident with wrenches.
"Police are aware on an intermittent basis, groups of youths come to the attention of police for their behaviour and they are dealt with on a case-by-case basis."
The spokeswoman said police encouraged anyone to report suspicious behaviour to their local station or call 111 in the case of emergencies.