Sydney’s property boom is close to breaking a 15-year record, with house prices surging 57.5 per cent in four years.

Results from the May CoreLogic RP Data Home Value Index show the median price of a dwelling in Sydney is now $782,000.

In the past four years, Sydney dwelling values increased 57.5 per cent, while Melbourne dwelling values are up 39.4 per cent and Brisbane increased 18.5 per cent.

Prices in Sydney jumped 3.1 per cent in May and 6.6 per cent over the previous three months, the strongest gains nationwide.

Core Logic RP Data’s latest home value index revealed the Harbour City’s median dwelling price, which includes units and houses, increased 3.1 per cent over May.

The increase meant the median price hit $782,000, the highest in the country and $192,000 pricier than the median in Melbourne, Australia’s second most expensive city.

Richardson & Wrench director and chief auctioneer Peter Baldwin said it was the longest and most sustained period of growth the city had seen: “It was a market fuelled on Red Bull and steroids at the beginning of last year … but this year it’s a nice tepid glass of water.”

Despite a slowdown in the early months of 2016, one reason for the jump in prices was a surge of investors into Sydney, CoreLogic RP Data head of research Tim Lawless said.

Investors staged a comeback into the NSW market in the latest official financing data for March, and it’s likely investors are at even higher levels now, he said.

“There have been announcements from the banking sector that they’re loosening up requirements for investors,” Mr Lawless said.

While HSBC chief economist Paul Bloxham agreed Sydney’s property prices had increased, he said it might not be directly a result of the interest rate announcement.

“The RBA will be watching the lift in prices as they’re really hoping exuberance in market is being contained by higher prudential settings… but it’s a little early to tell what result the May cut delivered,” Mr Bloxham said.

“The ramp up began in April and seems to have maintained momentum through May, but Sydney has already had a large price run up,” he said.

Melbourne’s annual growth is the fastest in the country at 13.9 per cent, with Sydney a close second at 13.1 per cent.

CoreLogic senior research analyst Cameron Kusher said the 57.5 per cent increase in house prices over the past four years in Sydney included some large individual yearly jumps.

“At the peak of the growth phase Sydney hit 18.4 per cent growth in the 12 months to July last year,” he said.