Wallace said expat buyers were looking to return to New Zealand for its family-friendly lifestyle.
Auckland QV valuer Glenda Whitehead said prices in the Auckland area, which increased by 5 per cent over 12 months, had also been affected by eager buyers keen to outbid one another at auctions.
"There are not that many properties on the market at the moment, so when something comes up that ticks everybody's boxes, they're all on to it like nothing on Earth.
"They get along to the auction and get a bit excited, and they mighthave a valuation or advice, say,of $800,000 and think, 'I'll go to $850,000'."
Whitehead said buyers had been known to get carried away at auctions.
"We do get the impression ... at some auctions there is a bit of face-saving ... [The] feedback we're getting is [when] it gets down to two people, [it's like they're] facing off against each other."
Despite this, Mr Wallace said he favoured auctions because they created a "fairer market value".
"Sometimes, the last bid comes down to the last $1000.
"You'd be hard-pressed to find a valuer that can be that accurate."
Figures from the QV index, released yesterday, showed all areas in Auckland experienced an increase in house prices above the national average.
The central area of Auckland City had the largest increase, with house prices up 7.9 per cent over the past year.
Properties in Manukau and on the North Shore both increased by 3.4 per cent, and in West Auckland, house values were up by 4.5 per cent.
In other parts of the country, increases in Whangarei house prices aligned with the national average, up 3.1 per cent.
Hamilton property values were up 1.7 per cent, and house prices in Tauranga and the Wellington area increased slightly over the past year, up 0.7 per cent and 0.6 per cent respectively.