Freyberg High School says the behaviour of some of its students after a protest while associate education minister David Seymour was visiting was unacceptable.
On Thursday, a student spat on the ground in front of the ACT leader during his visit to the school in Palmerston North.
A video shared online showed students performing the haka Ka Mate as he came outside.
At the conclusion of the haka, a student holding a tino rangatiratanga flag approached Seymour and spat at the ground by his feet.
In another video, students could be heard screaming "f... you".
School staff could be seen creating a human barrier between the students and Seymour.
Principal Graeme Williams said in a statement that some students' behaviour at the end of their protest was "totally unacceptable and contrary to the values and the high standards we hold ourselves to".
"Upholding the mana of our young people recognises the reality of their world but also that we must respect and uphold the dignity of each other and all guests at our kura/school.
"The matter will be managed appropriately through our disciplinary process."
A Wellington Regional Councillor has praised rangatahi at his old Palmerston North high school for protesting through haka over government policies.
Thomas Nash said the haka was a good way for the students to express themselves politically.
"I saw a group of young kids who were standing up for what they believed in, and who were carrying on a proud tradition of youth protest that we have in New Zealand.
"I'm also proud of the school for creating an environment where kids are aware politically of what's going on around them and how politics affects them."
Seymour said some of the students got "over-excited" and he would be happy to visit the school again.
Nash commended Seymour for complimenting the haka and speaking about going back to the school to meet with the students.
Seymour has come under fire in recent weeks for his plan to review the Ka Ora, Ka Ako programme, which provides free lunches to more than 220,000 students throughout the country.
According to its website, Freyberg has been a part of the programme since October 2021.
Seymour also faced opposition at the Waitangi Treaty Grounds this year, with the biggest challenge being lain down for him during the pōwhiri.
The other politicians were only greeted by one kaiwero (warrior), but Seymour had to face a group.
Seymour was also heckled by spectators while giving his speech at Waitangi, with some calling on him to sit down.
'Spitting is quite common in haka' - Sharples
A tikanga and haka expert is also backing the rangatahi, saying they upheld their tikanga while performing a haka at David Seymour.
Paora Sharples said spitting in haka did not break tikanga.
"The spitting is quite common in haka. Done many times at a national level, once again expression of just showing your distaste towards a particular kaupapa. In the old days, a whole manner of ways of expressing ones inner feelings was utilised and used through full affect during haka."
Sharples said the school needed to have a hui on the meaning of haka and how to utilise it.
"In the past, New Zealand society has been exposed, they tend to like the good side of haka and utilise it in that way but this is another aspect of haka that can be utilised to protest in this form. So it definitely needs to be sit down and be talked about," said Sharples.