An umbrella group for private tertiary institutions says the New Zealand Qualifications Authority (NZQA) is taking a tougher stance to root out poor performance.
The authority this week deregistered the Linguis International Institute due to widespread cheating, overcrowding and bad marking.
Quality Tertiary Institutions executive director Neil Miller said NZQA was doing more to make low-quality tertiary education providers improve or lose their registration.
"Previously they were quite hesitant when faced with legal action, and now they're beginning to confront it, and that is a step in the right direction," he said.
It was important that the authority weeded out badly performing institutions, he said.
"Low quality has to be confronted and dealt with and there have to be consequences for systemic problems like this - this is massive under-performance."
Mr Miller said the problems at Linguis, such as undetected plagiarism and poor marking, were basic errors it should have been able to fix.
Other investigations under way
Linguis is the third big enroller of foreign students to lose its registration in the past 10 months, following the Aotearoa Tertiary Institute and the International Academy of New Zealand (IANZ).
NZQA deputy chief executive quality assurance Grant Klinkum said Linguis used to have about 1000 students, mostly from India and China, but had just 81 at the time of its closure this week.
He said Linguis had ongoing and serious problems, including undetected and widespread plagiarism by students.
"What we have found is poor quality, unacceptable education standards," he said.
Dr Klinkum said NZQA had 45 investigations under way, but only a few involved problems that were systemic across an entire organisation.
"In all of those cases we have various interventions under way. Those interventions could range from not allowing the organisation to enrol any more international students, if it's more minor it could be an improvement plan required, or we may be proposing to deregister the organisation if there's ongoing and systemic problems."
Linguis challenged initial report findings, authority says
Dr Klinkum said Linguis had challenged the findings of NZQA's most recent External Evaluation and Review report, which delayed its confirmation until late last year.
The report was based on NZQA visits to Linguis' campuses in 2014 and 2015, and concluded that NZQA was not confident in the quality of education being provided.
It described problems with marking, students' poor command of English and widespread evidence of high rates of plagiarism.
"The scale of this plagiarism brings into question the reliability of the reported figures on educational achievement, and the processes leading to them.
"Some Linguis academic staff seemed unclear about what constitutes plagiarism, which in itself is likely to limit Linguis' ability to resolve the problem fully and satisfactorily."
The report said Linguis expanded rapidly from just 158 students in 2012, but that growth was badly managed and the resulting overcrowding had affected staff and students' well-being.
It said plans the institute had put in place to fix the problems had not led to demonstrable improvements.
RNZ has approached Linguis for comment.