The bank's economists say investors are taking the lion's share of high LVR mortgage lending in the three months to August.
Investors saw a 134% increase in high LVR lending (above 70%) in the three months to August, compared with the same period last year.
Owner-occupiers and first home buyers only saw a small increase in high LVR lending (above 80%) over the period.
The analysis offers further evidence that investors are the main beneficiaries of the Reserve Bank's April decision to scrap LVR speed limits for 12 months.
The high investor lending numbers are likely to draw scrutiny from the Reserve Bank. At a conference this week, governor Adrian Orr said the RBNZ was monitoring highly-leveraged investors.
ASB's latest observations come as the bank's economists revised their forecast for the housing market.
ASB economists, led by Nick Tuffley (pictured), now predict the housing market will soar by 12% by next June.
According to the bank's analysis, the share of overall new lending to first home buyers hit a high of 20% in August, with investors edging up their share to 21%.
Owner-occupiers continue to dominate the market, accounting for 58% of new home loans, down from 64% 18 months ago.