An academic is questioning the effectiveness of the Reserve Bank's new loan-to-value ratios.
In an opinion piece published on Thursday explaining why he brought in the loan restrictions, Governor Graeme Wheeler says excessive increases in house prices could put the economy and financial system at risk, and restricting lending to borrowers with low deposits could help slow down those rises.
Massey University School of Economics and Finance associate professor David Tripe says he's not sure that all of what Mr Wheeler says is valid.
Dr Tripe says the Governor asserts a number of things that are not substantiated by facts.
He says it's not clear that there is a real estate boom, rather than a rise in property prices in Auckland and Christchurch for reasons essentially related to shortages of housing.
Dr Tripe disagrees with the new loan restrictions, and says banks would be better protected if they were made to hold more capital.
He says if banks were required to hold more capital it would be likely to have the effect of slowing down their rate of lending on all housing, not just low high loan-to-value housing.
"That would probably in many ways be a more effective way of targeting booming house prices if those were in fact a problem anyway."
It also appears there was no rush to buy houses ahead of the introduction of the new loan restrictions.
Auckland realtor Barfoot and Thompson says the number of sales dropped 8% last month, although house prices continued to steadily rise.