ASB Bank and ANZ Bank New Zealand have followed Westpac Banking Corp's lead in clamping down on lending to property investors by requiring at least a 40 per cent deposit ahead of Reserve Bank restrictions.

Westpac made the same move on Wednesday after the central bank said earlier this week it intends having the new lending restrictions in force by September 1 and asked lenders to comply with the spirit of the new regulations immediately.

The regulations extend and expand the demand for a 30 per cent deposit on investment properties in Auckland introduced last year.

ASB said existing approvals and pre-approvals above the new 60 per cent loan-to-value ratio would be honoured until their documented expiry date.

ANZ, the country's biggest lender, said on Thursday that its maximum loan-to-value ratio of 60 per cent for property investors will apply across New Zealand. It was previously 70 per cent for Auckland.

It's also extended the 85 per cent ratio in Auckland owner-occupied homes across New Zealand.

The bank said it intends honouring all existing pre-approvals but any renewals will be subject to the new policy.

It said in a statement the changes were "a sensible and responsible response to market conditions".

The move follows comments on Wednesday by ANZ New Zealand chief executive David Hisco that property prices in Auckland were over-cooked and the ending of the property boom would be "messy".

He said "it's a matter of when, not if, the market adjusts".

Mr Hisco said the central bank needed to go further and demand 60 per cent deposits, which "will be unpopular amongst investors but it may end up doing them a favour".