Homes in popular tourist spots such as Queenstown do well on Airbnb.

If you've been looking for a new rental property lately, you might have felt there was little to choose from. It's not an illusion: the amount of available rental stock is dropping.

It's hard to get firm figures, but tenancy bond data from the Ministry of Business, Innovation and Employment shows the number of bonds lodged fell from 18205 in December 2016 to 17797 in December last year.

At the same time, the country's population grew by more than 100,000 people.

We'd love to hear your story - good or bad - about the rental market and what issues you think we need to explore. Email us at newstips@stuff.co.nz

Trade Me said the number of available rentals on its site was down 49 per cent nationwide in December and properties were coming on and off the market quickly.

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So what's caused the change? And is there any sign things will get better?



Not enough houses being built



Wait - isn't a shortage of new builds usually what we're told is driving house price rises?

ROBERT STEVEN/STUFF More residential houses are now on the short-term holiday home rental market - shrinking the pool of rental options.

The bad news is, it gets the blame for rental increases, too.

"In Wellington there's been so little increase in housing supply and whatever there has been has been going to owner-occupier stock," economist Shamubeel Eaqub says.

Construction firms want to produce properties that command the best price possible. That's not usually the type of housing stock that is destined for the rental market.



There's also no incentive for investors to fork out on expensive new builds, when the rent they'll earn doesn't cover the cost.



"When rental yields are so low, unless you expect capital gains it doesn't make sense to build a lot of stuff," Eaqub says.



Usually, you'd expect to see older properties "seeping out" into the rental market, as people upgraded to flash new properties. "But for whatever reason we are not seeing a lot of that."

GETTY IMAGES Listings on Airbnb jumped 93 per cent in the last year in Auckland alone.

Eventually supply will catch up, he says, but it could take years. "Except in Auckland where we never seem to build enough. But when there is not enough supply it's most likely to affect those at the bottom end of the housing spectrum."

People moving home from Australia

As the economy improved in New Zealand and faltered in Australia, there were lots of headlines about more migrants jumping the ditch in New Zealand's direction.



But while it would reduce stock if people were returning from Australia and moving back to properties they'd rented out while they were away, there's no evidence that's actually happening.



"New Zealanders are still going to Australia," Eaqub says.



​What is true, though, is that more people are shifting to New Zealand and looking for somewhere to live, which puts pressure on the rental market. The population grew by 100,400 in the June 2017 year.

SUPPLIED Andrew Bruce says fewer investors are members of the Aukland Property Investors Association.

Investors getting out

There is anecdotal evidence that the prospect of tighter rules for landlords, and less opportunity for capital gain in a slower market, is making property investment a less enticing prospect.

If fewer landlords own properties, it follows that there would be fewer available for rent.

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Andrew Bruce, president of the Auckland Property Investors Association, says his organisation's membership has tapered off over the past few months.

When people were asked why they left, they said they were selling up, that it was becoming too hard to be a landlord, or they were not able to borrow any more money, he said.

While there was always movement in the membership, it had become more noticeable recently. "We haven't had the same levels of inquiry we normally get, either."

But Eaqub said if investors were getting out, they seemed to be selling to other investors, which would keep the number of available rentals stable. "The number of homeowners isn't increasing."

Economist Gareth Kiernan was unconvinced, too.

"Firstly, house sales volumes have been low. Secondly, first-home buyers have largely been priced out of the market due to high prices and deposit requirements to meet the LVR restrictions. And if you're going to blame a drop in the rental stock on investors cashing up, that also equates to a drop in the demand for rental accommodation, as all the first-home buyers must have been people who were previously renting."

Landlords being pickier

Eaqub says that when the rental market is tight, it leads to a drop in bond numbers because landlords streamline their businesses.

People who let to multiple tenants - such as a landlord with student flatmates sharing a house and who took a bond from each - might decide instead to let to a professional couple or family on one tenancy.

"They prefer someone who will look after the place."

Airbnb

The short-term letting platform often gets the blame - particularly when there are stories of landlords doubling their money by opting to let via Airbnb instead.

There are other benefits for investors, too: Properties offered as short-term leases will also likely not be caught by the new rules imposing minimum insulation and heating standards on rental properties. Buyers do not have to have the usual investor requirement of 40 per cent deposit if they are to let a house out for 47 nights a year or fewer.

In Auckland, where there are about 4700 entire properties listed for short-term rental on Airbnb and a further 4400 private rooms for rent, the total number of listings increased by 93 per cent in the past year.

In Wellington, there are about 1600 entire properties listed on Airbnb - three for every for 100 ordinary rentals - and 770 private rooms.

But while it might make a difference somewhere like Queenstown, Airbnb is only a marginal factor in cities such as Auckland and Wellington. Economist Cameron Bagrie, of Bagrie Economics, says the numbers involved are small.

"You'd need pretty high occupancy to make it work, and costs of turning over short-term stays needs to be taken into account, and you have more 'risk'."

Bruce tried to let one of his Auckland apartments on Airbnb when his tenant went travelling for six months.

"It didn't work that well." He offered the property for $100 or $110 a night and did not come close to replacing the usual $320-a-week rent. Other landlords reported problems getting their listings ranked up on the site and a single negative comment making it tough to get bookings.

Airbnb says its platform can make housing more affordable because it enables owners to make extra income from it.

A spokeswoman said in Rotorua, where moteliers have raised concerns about Airbnb, the median rent for a three- or four-bedroom property is $380 per week or $19,760 per year. "In contrast, the typical Airbnb host in Rotorua is only earning $165 per week or $8600 a year."

Fewer people moving

Jeffries says the rental market is changing as it becomes harder for people to buy their first homes. People stay in rental properties longer as they save, or become long-term renters.

"With more tenants staying put this has resulted in fewer rentals coming on to the market.

"This, to some extent, has a snowball effect as those contemplating moving into a new rental can see limited stock and therefore choose not to move, which further exacerbates the lack of supply of rental properties."