Affordability isn't the problem. Poor saving and financial habits are.

Housing affordability.  It's enough to make anybody break into a cold sweat and feel defeated.  Especially if you're a 20 something, but let's look at it another way.

Imagine you're on $50,000 and have no responsibilities like kids, that's about $800 per week after tax.  Now imagine you pay only $250 rent a week, possibly $150 for all other compulsory expenses and say $50 for leisure (clothes etc).  That still leaves you with $350 a week to save.  That would equate to $1400 a month, which is $16,800 a year.  Then add on the annual tax refund of an average of $3000 in Australia.  Right there you have $19800 saved in one year on a modest income.  Now say you want to get a 15 year mortgage on a $400,000 property in Sydney's west or buy an investment property in NZ for $200-$300,000, you would have your deposit right there in 3-4 years.  It's doable in two years but let's go conservative and say 3-4 years to reduce the length of the mortgage.  Presumably you'd have tenants in the investment property so you'll still be able to rent and own.  Once your investment property is paid off you can use the profit to either buy a second investment property (so have two at once) or buy a home in a suburb you want to buy in.

Aussies and Kiwis are notoriously terrible savers.  Our parents generation saved on low incomes but our generation, the iWant generation thinks the Government should hold our hands.  

People need to start planning their financial futures while they have no kids and can because if they don't they'll just end up in a cycle of poverty.  Affordability isn't the problem, expectations are yet the NZ National government thinks promising people $20,000 will solve the problem.  It won't.  All it does is create further generations of people not taking responsibility for their futures or finances.