House prices are booming around New Zealand - with the average price of an Auckland city home rocketing to $735,692, up 12 per cent over the past year.

Auckland's top real estate agency has welcomed the Reserve Bank's moves to dampen the hot housing market but doesn't expect prices to suddenly drop.

The Reserve Bank has given strong signals that it intends to restrict mortgage lending at high loan-to-value ratios, to rein in credit growth and house price inflation.

The Reserve Bank of New Zealand says it intervened in foreign exchange markets in an attempt to drive the kiwi lower. It gave no details of the size of the intervention.

The Reserve Bank would impose limits on riskier mortgage lending with smaller deposits if it judged those loans to be a "significant risk" to financial stability.

The dollar rose as much as 0.7 per cent against the greenback after Reserve Bank governor Graeme Wheeler backed off from talking down the currency at today's monetary policy review.

"While there's been much hand-wringing over housing prices, is intervention by the Reserve Bank really the answer?" asks David Tripe.