Schools have lost $40 million in international student revenue during the Covid pandemic - and it's expected to get worse.
Official Information Act documents provided to Newstalk ZB show primary, intermediate and secondary schools made just over $179 million from international students in 2019, and that dropped to $139m last year.
Eleven thousand foreign pupils attended primary, intermediate and secondary schools here in 2019, but that dropped to 9100 last year.
This year's enrolment and revenue figures aren't yet available.
The Ministry of Education says the full impact of Covid-19 and the global financial downturn is just beginning to be felt.
Next year is expected to be the lowest point for international student enrolments at New Zealand schools.
Spokeswoman Cathryn Ashley-Jones says international students who arrived before the border closures are completing their programmes, so numbers are falling.
She says with so few new students, there'll be a long-term impact on revenue.
Ashley-Jones says even once they can return, numbers will likely take considerable time to rebuild.
That's due to long recruitment, fewer education agents and marketing opportunities, and the impact of the global financial crisis on students' finances.
Secondary Principals' Association Vice President Vaughan Couillault agrees it could take time to rebuild.
However, he says New Zealand has done such a good job providing international education and he hopes people come flooding back in as soon as the doors are open.
Couillault expects schools to make cutbacks as more foreign pupils head home.
He says some of the international fees are spent on teaching ESOL - English for Speakers of Other Languages - but a lot of it goes towards other things.
For example, the money could be used to reduce class sizes to 18 or hire external sports coaches.
Couillault says some of the international student fees have been used to help pay for te reo classes at his school.
More redundancies are expected at schools next year because of a lack of international students.
Couillault says a lot of teachers lost their jobs at the end of last year, as overseas students left.
He says there could be more restructuring next year.
Waihi College principal Alistair Cochrane told Newstalk ZB's Mike Hosking this morning that staff at his school had lost their jobs due to the pandemic hitting international student numbers.
The school normally had around 35 international students but that funding had stopped coming in.
Cochrane said the decision was originally made to start marketing to international students because Waihi College couldn't balance the books for the programmes they wanted to put in place without them.
"You could argue to do the things we really want to do we're not being funded adequately by the Government."
Some staff had been put on retainer in the hopes that international students would be back but he had "no confidence" of that happening in 2022.
Meanwhile National says slow Covid-19 vaccine rollout has had an impact on schools' international student revenue.
Education spokesman Paul Goldsmith says many schools which relied on income from overseas students are doing it tough.
But he says the broader issue is doing what we can to open up our economy, which means getting vaccinated.
He says the Government had one job to do this year - ensuring we got the vaccines as soon as possible.
Goldsmith says we're playing catch-up now but the rollout's been far too slow, which has extended the pain.
He says getting the country vaccinated is the only way we'll be able to welcome international students back into the country.
Goldsmith says that's been challenging because New Zealand has had a slow vaccine rollout.