Older immigrants enrolled in tertiary study in order to access interest-free student loans because they were not eligible to get benefits or superannuation, Tertiary Education, Skills and Employment Minister Steven Joyce says.
Mr Joyce said there was "significant evidence" of the practice, and made his comments in explaining why the numbers of older tertiary students have dropped.
The national student union and lobby group Grey Power publicised the drop in older student numbers yesterday, and blamed Government cuts.
The total number of New Zealanders aged 55 and over enrolled in tertiary study has dropped from over 33,000 in 2008 to less than 19,000 in 2014, Grey Power said.
Grey Power president Terry King said the Government had cut support for life-long learning.
"The Government's cuts to allowances for over 40s were bad enough, but preventing over-55s from accessing any allowances or even a loan to pay the bills has led to a crash in the number of older Kiwis studying.
"Age discrimination is never acceptable and we see now its consequences."
However, Mr Joyce said it was important to note that the number of full-time equivalent students aged 55 and older studying at the degree level and above was slightly higher in 2014 compared with 2008.
He said the decline in older student numbers was due to three factors, the first of which was more people aged 55 and older were working.
The Government had also phased out low-level, part-time short courses since the mid-2000s, which Mr Joyce deemed to be of "very low value".
"Thirdly, the government stopped loaning for living costs to those over 55 in 2013, because it is hard to justify that taxpayers should pay the high costs of interest-free student loans for older people to leave the workforce and go and study full-time.
"There was also significant evidence that some older immigrants were enrolling in courses and taking out interest-free student loans because they weren't allowed to receive benefits or superannuation."
Mr Joyce said the current approach was fair and was focussing limited resources on providing loans and allowances to younger people, who were studying before entering the workforce.
National student union president Rory McCourt labelled the year on year fall of over-55 students under National as "embarrassing."
"It's an embarrassing record for a party that says they're committed to work and growing the economy," he said.
"Governments of any colour have to realise that we need to support life-long learning.
"Older Kiwis need to know that there will be assistance to retrain and up-skill if they lose their job or their industry changes."