PHOTO: The five-bedroom residence with a tennis court and pool is set on 1085 square metres. Photo: Supplied

While many of the nation’s 20-somethings are contemplating how to gain a foothold in the property market, Junlin Lan and Hairu Yang are upgrading to a $24.6 million house – Australia’s most expensive house sold at auction.

The buyers of the Vaucluse mansion, formerly owned by the late Japanese businessman Akihiko Terada, have remained a tightly guarded secret since the hammer fell on the historic auction in September, despite the bullish result being more than $10 million over the reserve.

Lan and Yang, 26 and 29 respectively, are already luxury home owners in Sydney, having purchased the two-level penthouse atop atop the Swissotel in the CBD three years ago for $10 million from hair salon founder Christine Warbrick and her late husband Warwick.

The Vaucluse Road residence was commissioned 15 years ago by the Kariappa family. Photo: Supplied

The young couple, originally from China, outbid 11 other bidders at the Sotheby’s International auction, at which the opening offer of $13 million was well above the $11 million guide offered to Domain by selling agent Michael Pallier the day before. More than half of the 25 registered buyers never raised their hand at the auction.

A reserve of $14 million was also left far behind as bids of $100,000 saw the result pushed to $24.6 million.

The result eclipsed the previous national house price auction result set in 2009 at $23 million when media boss Lachlan Murdoch and his wife Sarah bought the French government’s official residence of its trade commissioner, Le Manoir, in Bellevue Hill. At the time Le Manoir had a guide of $15 million.

The $24.6 million sale eclipses the $23 million auction record of 2009 when the Murdoch family bought Le Manoir in Bellevue Hill.