100 complaints have poured in to Grant Robertson's office, after he asked Wellington students to dob in any landlords illegally raising rents too far.
On Friday the Wellington Central MP used his Facebook page to ask for stories from renters whose landlords were "exploiting the situation".
"My office is getting stories of $50 per week increases on the basis that student allowances and living cost payments have gone up by that much.
"Let me know if this has happened to you. Landlords will increase rents from time to time but it needs to be fair and reasonable.
"Let's expose those who are exploiting you and your friends."
The Facebook post has attracted 1300 reactions, and almost 400 comments. A spokesperson for Robertson's office said they'd had around 100 official complaints sent in through Facebook and email.
Nicki Eldridge is one of those who has come forward, after she and her three children were forced to leave the house that was their home for the past six years.
Just before Christmas she was given 90 days' notice that the landlords were ending her periodic tenancy agreement. It was then listed on the market for an extra $80 a week.
"I said that's really strange, I've been a really good tenant, you've always given me really great feedback. Can I have a conversation about it?
"And they were like 'no, landlord doesn't want to talk to you'."
Eldridge and her children were eventually forced to move from their Thorndon home, where she could walk to work, to a house in Petone, with a much bigger commute.
"I found it really difficult to find a new property, was really stressed about it.
"Especially with my kids, being a sole parent in Wellington. I've gone through the same nightmare as everyone else, going to viewings where there's 30-40 people wanting a house that is dark, wet, damp.
"In the end I just had to accept I was moving out of town."
Another 29-year-old renter, who didn't want his name used in case of backlash from his landlord, said he suspected their rent was put up $50 because of the $50 increase for students.
That was despite no one in their flat being a student.
"He manages a few student flats, so might just be tacking us on, too.
"In my opinion, our landlord has merely taken advantage of this recent mass $50 increase to convince the house owner our rent is too low."
The renter said he felt exploited.
"Almost all improvements made to the house have been done by me free of charge as he has no interest in doing much.
"I've practically turned this house from a trashed student flat to a little palace.
"He's a lazy bludger."
Renters United organiser Anna Mooney said Wellington renters were all starting to struggle.
"Right across the board people's rents are going up massively. They were already very high, and they've only climbed higher this year."
Mooney said the cause seemed to be a mixture of low supply and landlords charging more in a tight market.
She said there was no doubt people felt the pressure to accept the "ridiculous" prices, "or you're going to be homeless, essentially".
Mooney said there were two sides to fixing the problem.
"Supply needs to be increased. We need more houses in Wellington, and around the rest of New Zealand too.
"But also, we really need some form of rent control, to limit these rent rises.
"Maybe you could tie it to how much rates are going up, or the minimum wage.
"We just need some way to stop landlords taking advantage of the market, and putting up rents as high as they can."