Education Minister Hekia Parata has referred to anti-apartheid protests while criticising secondary teachers for discriminating against staff from charter schools.

Photo: RNZ / Alexander Robertson

She told the Post Primary Teachers' Association's conference in Wellington today that Northland teachers had treated a local charter school teacher unfairly.

She said the publicly funded private schools were part of efforts to address under-achievement.

"I rely on your professionalism and capability to help with the kaupapa, not boycott it. This is New Zealand - many of us took to the streets in 1981 to oppose discrimination in another country."

Ms Parata said her only disappointment with the union was its opposition to the schools.