"At Harcourts, we have known this was coming for some time and I have been calling for a revision of the new builds process. Until gaining building consent is easier and loss costly, prices will continue to rise," Kennedy said.
Nationally last month, the number of houses for sale at Harcourts was only 6407, a "huge" 26.2 per cent drop on the same time last year, Kennedy said.
The average national house price was $548,208, he said.
In Auckland, stock numbers fell 3.1 per cent in April, and only 1600 residential properties were on the market.
The average Christchurch house price last month was $550,529, up 4 per cent on the same time last year, he said, raising concerns about that city's situation.
Of concern was the level of housing stock in Christchurch which is continuing to drop. New listings were down by 26.7 per cent on the same time in 2015 and total property available to buy was down 23 per cent, with just 1628 houses on the market.
Wellington prices had risen 5 per cent and stock had fallen 45 per cent in April compared to the same month last year.
Meanwhile, the Reserve Bank is considering income-related lending restrictions to top people borrowing too much compared to their incomes.
However, Finance Minister Bill English has signalled that further steps to address housing shortages in Auckland will be announced in next Thursday's Budget.
That would include announcements around the strategy "of working with the council to get more houses on the ground faster and getting the Government using its own land and housing in Auckland to help the supply problem," English said last week.
