Raewyn Tipene, the chief executive of the trust establishing Te Kura Hourua ki Whangarei Te Renga Paraoa and the director of the Leadership Academy, said she feared the PPTA's stance would result in vulnerable Northland children being left behind.
There are 38 boys in the Leadership Academy and enrolled at schools in Whangarei.
If the boys and their whanau choose to enroll in the kura hourua, the kura has plans for some senior students to take certain classes, such as economics or trade studies at external schools such as Whangarei Boys' High School and NorthTec.
The ban on interaction between PPTA members and charter schools means this couldn't happen and students would miss out on opportunities.
"The principals [in Whangarei] are rattled. They are being stood over by the PPTA and they have no room to move," Ms Tipene said.
Whangarei Boys' High School headmaster Al Kirk said until the union held a meeting with members next week he was not sure what the future relationship between his school and the Leadership Academy looked like.
The president of the PPTA, Angela Roberts, told the Advocate communities thinking the charter schools would raise Maori achievement were mistaken.
"We get the frustration in these communities, but [charter schools] is not the solution," she said.
She said the kura would mean roll declines for other schools in Northland and fewer resources for the schools and, ultimately, the threat of lost jobs for PPTA members.
"We're ready to fight [charter schools] all the way," she said.
Ms Roberts is flying from Wellington to Whangarei on Tuesday, November 19, to talk to members about their options.
Natasha Sadler, curriculum director for Te Kura Hourua ki Whangaruru, took the opportunity to dispel some myths at a series of community hui in Northland recently.
"A common myth is that the kura will have unregistered teachers - we have hired four registered teachers and hope to hire more," she said.
She also said the kura would be teaching from New Zealand curriculum.
Both kura hourua directors said registered teachers and staff had been vetted by the police.
Te Kura Hourua ki Whangaruru will have 71 students next year and Te Kura Hourua ki Whangarei Te Renga Paraoa will have 50 students.
They will soon start taking enrolments: Te Kura Hourua ki Whangaruru for Years 9 to 13 and Te Kura Hourua ki Whangarei Te Renga Paraoa just for Year 9. They will be ready to open for the 2014 academic year.
Te Kura Houoria ki Whangaruru has another hui in Whangarei at 35 Rathbone St on Thursday, November 14, at 6pm-8pm.