The property market appears to be holding its breath ahead of major changes to lending, one economist says.

New data out from industry website realestate.co.nz showed the Auckland market softening last month and that nationally new listings are down to an all-time low, indicating people are uncertain about selling their houses.

The website said Auckland had become a buyers' market, based on its inventory figures. It would now take 24 weeks to sell all the houses for sale in Auckland, if no other listings were added to it, surpassing its long-term average of 23 weeks.

Realestate.co.nz said it was the first time since February 2011, nearly 7 years ago, that Auckland had been in that position.

However, sellers hadn't adjusted their price expectations, with the average asking price up 2.7 per cent to $982,673 from November.

"Auckland saw new property valuations last year, which may be leading vendors to expect more than the market wants to pay," Vanessa Taylor, a spokesperson for realestate.co.nz said.

While new listings in Auckland were down 7.8 per cent on the previous year, the total number of listings or "stock" has swollen considerably.

ASB economist Kim Mundy explained that when new listings fell but the "stock" grew, it signified that sales had dropped.

That's what she believed as happening more or less nationally - that people had held off buying or listing because of uncertainty, firstly because of the election and then a traditional pause at Christmas.

"There are a lot of changes coming in 2018, so it does make sense that people would just hold off if they could and see what 2018 has in store," she said.

Changes in the wind include the eventual easing of "LVR" or mortgage loan criteria on both owner-occupiers and investors, and also the Government's promise to clamp down on foreign buyers.

But even after the seasonal effects had been taken into account, Auckland was still soft and it would not be until early to mid-2018 before it was clear whether it was a permanent slump.

Listings appeared to be building in other major centres, too. Despite a year of red-hot real estate activity, Wellington's total stock was 21 per cent higher than the end of 2015, although both stock and new listings dropped on the previous month.

Asking prices in the capital were flat since November at $573,968.

"It appears in Wellington that both buyers and sellers were very cautious in the final month of 2017," Mundy said. "

However, there was little sign of demand petering out in the Wellington market yet – its inventory would take just an estimated 7 weeks to sell out, instead of the usual 18 weeks.

In Canterbury housing stocks were up 18.6 per cent on year-ago levels and asking prices were up 4 per cent to $501,665.

On a national basis, housing stocks were up 9.3 per cent on a year earlier, but the inventory was almost half its long-term average, 18 weeks instead of 31 weeks.

New listings were down 6.2 per cent, to an all-time low, and the average asking price hit an all-time high of $660,798, up 3.8 per cent since November.

Sellers in Central Otago had the highest asking price expectations in the country at $984,719, although this did not necessarily reflect the sale price.

Other places to see big jumps in asking prices were Nelson & Bays (up 11.3 per cent to $618,712); Marlborough (up 10 per cent up to $479,288); the West Coast (up 8.7 per cent to $265,396); Southland (up 6.3 per cent to $309,174); and the Wairarapa (up 5.4 per cent to $429,488).

The biggest drops in asking prices were seen in the Central North Island (down 7.4 per cent to $403,648) and Gisborne (down 4.7 per cent to $287,928).