Auckland first-home buyers' wages are nowhere near keeping up with the increase in the city's house prices a new report into housing affordability shows.

Even cheaper houses in almost all regions of New Zealand are affordable for couples in the prime first-house buying age bracket – except for Auckland.

In July 2013 the REINZ's lower-quartile selling price in Auckland was $444,000. By December 2015 it had increased to $624,000, up by $180,000, or just over 40 per cent, in two-and-half years.

Over the same period, the combined take-home pay of a typical first-home buying couple increased just $62.40, or 4 per cent.

Mortgage payments of up to 40 per cent of take-home pay have traditionally been considered affordable. By December 2015 the mortgage payments for lower-quartile Auckland houses were $767.29 a week or almost half the buyers' take-home pay.

While anecdotal evidence suggested changes to the rules at the end of 2015, which restricted low-deposit lending to investors, introduced a bright-line test for capital gains tax and required investors to have an Inland Revenue number, had caused a drop in investor interest, the affordability problem remained.