Reserve Bank restrictions on bank lending to property investors have eased this month with the equity requirement dropping from 40 per cent to 35 per cent.
But Jackson said even with the easing it was an investment that still tied up more capital than was historically the norm.
"Previously, investors could recoup this with strong capital gains, but with a slowing property market investors are now unsure if any net gain will be realised.
"Coupled with low and stagnating rental yields, property investment is losing its shine for many."
Jackson's view comes on the back of a property investors survey which found landlords welcome longer-term tenancies but are cautious about other proposed changes to tenancy law.
The research by the Auckland Property Investors' Association polled more than 500 active Auckland landlords about the extent to which they expected to be affected by various proposals related to the residential tenancy market.
Landlords across the board responded favourably towards the relaxation of loan-to-value restrictions, better security of tenure through longer-term tenancies and the Healthy Homes Guarantee Act, the association said.
The survey found that landlords were most concerned about the prospects of a capital gains tax, debt-to-income restriction, and the removal of the 42-day notice to terminate.