We may not have seen the last of Reserve Bank intervention in the housing market, experts say.

Loan-to-value restrictions limiting lending to investors with deposits of less than 40 per cent officially kicked in this week. Banks had been required to act in the spirit of the rules since they were announced in July.

Corelogic analyst Nick Goodall said they seemed to be having an effect on the market.

He said bank-ordered valuations, used to support lending decisions, provided a good measure of future demand.

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"In Auckland these remain flat compared to activity prior to the loan-to-value announcement in late July. This is seasonally very weak as we would have expected activity from mid-winter to pick up in September," he said.

"Outside Auckland, activity hasn't been quite as subdued with a small lift from winter but nothing like the lift we saw last year and that we would typically expect in September."

Hamilton's volumes were down about 5 per cent compared to winter and Tauranga had recorded a significant drop in the past fortnight.

Whangarei was also below winter levels. All three centres had previously benefited from their proximity to Auckland, but looser lending requirements.

But Goodall said the factors driving house price increases had not disappeared.

"While demand has been hit by the latest round of loan-to-value limits, the low interest rate environment still makes borrowing attractive for those able to get the required deposit. And while the net migration 'tide' had started to turn, including back across the Tasman, the latest figures showed a flattening of migrants into the country and stalling of those leaving. This means we're still seeing a strong overall inflow and therefore more people looking for homes," he said.

"Then on the supply side, specifically in Auckland, the Unitary Plan should start to have an impact but as with any development/regulatory changes it's going to take a while for processes to catch up so options for buyers will remain constrained for the time being.

"All of this means it's unlikely that values will be heading south any time soon, which will no doubt continue to draw the attention of both the Government and RBNZ. My pick? More intervention to come."

BNZ chief economist Tony Alexander also expects tougher rules may be just around the corner.

He said the housing market had gone into a holding pattern since the requirement was introduced – but this quiet period was only likely to last three or four months.

"That means the Reserve Bank will probably raise the minimum from 40 per cent next year and implement restrictions on mortgage sizes as a multiple of household incomes of the borrowers. As always as has been our key point since the middle of 2009, the incentive for people contemplating making a purchase remains buy now rather than wait when prices will be higher and lending restrictions tougher."