Renters whose freezing homes won't be insulated before new regulations come into effect next month say they have no power in getting their landlords to bring them up to scratch.
From July, landlords must ensure their rental properties have floor and ceiling insulation where possible.
A manager for the Ministry for Business, Innovation and Employment (MBIE) Steve Watson estimated 100,000 properties did not meet those standards.
Mr Watson said that was concerning.
"The intent of the legislation, which was passed back in 2016, was that as many of New Zealand's rental properties where practicable should be fully insulated and landlords have had considerable time to do that, and it appears that they have not acted."
For landlords who have yet to book in to have their homes insulated, it's unlikely they will make it in time for the 1 July deadline.
Insulation companies are reporting backlogs until the end of next month and Anne Fletcher of Auckland Insulation said some could be waiting until August.
"Don't be thinking that you can ring a company in the last week of June and think that you can get the job installed in a week, because it ain't going to happen."
Mr Watson said there would not be any extensions granted for landlords who did not have their homes up to the new standards by 1 July.
Landlords who do not comply could face fines of up to $4000 but Mr Watson urged tenants to speak to their landlords and try to work things through with them in the first instance, before contacting MBIE.
"I believe that most landlords want to do the right thing and have been slow to act and have now been caught out by the fact that there is a limited number of suppliers," he said.
Wellington renter Hayley - who lives in a freezing cold, damp flat - said it was totally unrealistic for renters to call landlords to account.
"If there's record of you going after a landlord for a fine then that will travel with you even if it's not in the immediate term.
"I think that landlords do have the power in this situation and I think that property managers are always on side with them, rather than tenants."
Hayley said she and her two flatmates paid $610 a week for their flat, which had no insulation, was damp and had no heating sources.
They wrap up with hats, blankets and hot water bottles to try to keep warm - and Hayley said she did not expect that to change by next month.
"You kind of get a feel for what your landlord's going to be like with other, littler things.
"There's been a leaking tap ... since I moved in months ago and the landlord said someone would look at it but that's never happened.
"Personally, I know they're very unresponsive so why would I really even bother with pursuing anything else?"
MBIE said it had 27 staff in its compliance and investigations team to investigate complaints about rentals which are not insulated come 1 July.