English New Zealand represents the largest such schools in the country. Chair Darren Conway said there were only about 25 schools left and they were now down to just a handful of students each or none at all.
He said emergency government funding for the schools would finish in a few weeks and most would not be able to continue without that money.
He estimated most would have to close within three to four months and all would be shut by the end of this year.
"We're all teaching out our last few students that were left here from before the border closing and most of the schools have only a handful if any students," he said.
"If we don't get some support pretty quickly most will have to either close permanently or hibernate if it's possible for them."
Conway said it would be difficult for the schools to reopen after the borders opened to foreign visitors.
"Firstly; you'd have to get space, secondly; the space would have to be outfitted properly, thirdly; you'd have to get the staff for teaching and that takes time to recruit back up from very low numbers - zero or a handful of teachers that people have got at the moment. And the other thing is you can't just switch on and think the students are going to turn up. Some of our students are booking a year out," he said.
Universities' language schools were likely to continue because the universities could afford to support them and they would have a good supply of students on academic preparation courses, he said, but the rest of the sector might never fully recover.
"The universities play a vital role in the English language teaching industry but they're not anywhere near the bulk of the business and they have quite a different market from the broader language travel market that is the bread and butter of this industry worldwide," he said.
Conway said the situation was a disaster.
The schools enrolled nearly 29,000 students a year in recent years, but they had almost no new enrolments since the borders closed a year ago.
Education Ministry documents showed the government was warned of the problem in April.
A summary of workshops held with organisations that enrolled foreign students said the English language subsector was one of the most impacted by Covid-19.
"They identified a risk that the entire English language subsector will not exist by the end of the year. Staffing has been reduced across the board, a number of English language schools have closed, and a number of other schools are considering their options beyond June.
"Representatives were concerned that 'fly-by-night' providers may enter the sector if category 1 and 2 providers had to exit due to financial pressures," the summary said.
