House sellers have been smiling all the way to the bank but that is likely to change, according to a new report.

Property research company CoreLogic's latest "Pain & Gain" report shows a record 99.3 per cent of properties resold in the December quarter made a profit.

The median sales gain rose $42,000 to $420,000, while median loss eased to $20,000 from $35,000.

CoreLogic chief economist Kelvin Davidson says the higher gains in a sellers' market is no surprise, and it can be expected to persist for a while even with falling prices.

"Looking ahead, it would not be a surprise to see these 'pain & gain' figures soften next quarter given that there are much clearer signs now that the property market itself has passed its peak growth phase.

"However, the softening for 'gain' may be gradual, given that long hold periods strongly influence the data."

The strength of the gains was across the board regardless of location and type of property.

However, Davidson notes the "profits" on sales are largely on paper.

"These resale gains are not generally cash windfalls - unless they're downsizing or moving to a cheaper location. After all, in most cases, any equity accumulated needs to be recycled straight back into the next property purchase, with 'trade ups' actually likely to involve higher debt levels in many cases too."

Wellington has the highest "gain" with a median resale profit of $593,000, while Tauranga has the highest level of gains - 99.8 per cent of all sales are profit making.

Property owners are holding on to their houses just over seven years before selling.

Davidson says with clear signs that the property market has peaked and prices are likely to fall, the balance of power in the market is changing.

"We suspect that a shift in the balance of pricing power away from vendors and towards buyers is now in progress, which will dampen resale performance in 2022."

-RNZ.