It comes as house prices continued to boom in February, despite changes to loan-to-value ratio rules making it harder for investors to access mortgages.
Auckland's median sales price soared to $1.1m, while national prices climbed to $780,000.
One three-bedroom Grey Lynn villa earlier bought last August was resold last week for a $755,000 resale jump - netting its owners more than $100,000 in capital gains per month.
The three-bedroom Grey Lynn home at 3 Schofield St sold at auction for $2.55m after the owners earlier paid $1.825m for it in August.
Marketing photos from the time appeared to show little had been done to improve the property leading up to its incredible resale profit.
When contacted by the Herald, the owners did not wish to talk about the resale.
But they appeared to run a home renovation company and may have done work on the home prior to relisting it.
Other properties fetching stunning prices included a Sandringham 1900s bay villa that sold at auction on Friday for $3.8m.
That was close to $1.5m above the four-bedroom home's $2.35m council valuation and way above its $3.3m pre-auction offer.
The smartly renovated home came with a modern open plan kitchen and living area and a 642sq m block "in a coveted location on the city fringe".
But among the hottest properties for sale were those with potential for developers to build multiple townhouses or apartments on the site.
Michelle Russell said the Northcote tennis court land was earlier bought by her father Raymond Russell for £500 in 1956, according to Stuff.
He later built the tennis court, which became a neighbourhood hub as children flocked there to play, Russell said.
