The new regulations, which come into effect July 1, require all rental properties to have ceiling and underfloor insulation.
WarmUp Solutions owner Steve Dunbar, of Dunedin, said he had been incredibly busy recently.
"My turnover is three times what it normally is.''
There was a higher demand for materials, which was having a knock-on effect of more pressure on manufacturers as well.
"There's also regular DIY home owners picking up anything they can get their hands on.
"Factories can't manufacture the stuff fast enough.''
Salmac Insulation owner Mike Lea, of Dunedin, said he had also seen an increase in business lately, due to the approaching deadline.
"I'm a little surprised they've left it late.''
He also said finding materials was a challenge.
"Obtaining materials is difficult because the factories are under the pump, churning them out.''
Auckland insulation manufacturer Mammoth Insulation was "stretched but coping'' with the demand from around the country for materials, director Paul Thomson said.
"We're at our peak. We can double our efforts, but no more than that.''
Dunedin's Cosy Homes Trust project manager Jordana Whyte said she was not sure why so many landlords were scrambling at the last minute.
"The new regulations are not new information.''
The trust provides warm and healthy homes information, resources and referrals.
If a property is not insulated before July 1, landlords may face a penalty even if they are on a waiting list with an installer.
Ms Whyte said there was no grey area in the new regulations.
"The Government are taking a hard line approach.''
The pressure is also being felt in other regions.
Ilona Douglas, of Green Dog Insulation in Christchurch, said it was working on all kinds of rental properties, from student flats to regular residential at present.
"We are absolutely inundated with people doing it at the last minute.''
Awarua Synergy general manager Sumaria Beaton, in Invercargill, said she had been only able to give out quotes for some jobs.
"We just don't have enough guys to go out on jobs.''
