Four companies signed up to bid on the three-bedroom duplex at 1/12 Waitovu Street, just down the street from Balmoral Beach and Bathers' Pavilion.

This is one of 819 homes scheduled for auction in Sydney on Saturday. As of Saturday evening, Domain Group recorded a 71.2 per cent preliminary auction clearance rate out of 552 reported results, while 105 auctions were withdrawn. The withdrawn auctions were counted as unsold properties when calculating the clearance rate.

The Mosman house opened with a bid of $2.5 million - well below the $3.5 million guide price - but had reached $3.65 million by the fifth bid. The seller then placed a reserve bid of $3.75 million, which was eventually topped by a bid of $5,000.

During the thirty-minute auction, four buyers made offers and the home sold to a Mosman couple who bid over the phone. The couple, who will soon be empty nesters, will likely rent out the property for a short period before downsizing.

Adrian Bridges, selling agent from Atlas Lower North Shore, said the duplex's proximity to the beach and its house-like proportions made it popular with buyers.

"As a lower duplex it has a homely feel to it, albeit in a self-managed split level with only one other person. The previous owners have renovated the kitchen and bathrooms beautifully and have retained the Art Deco character.

Bridges says the market for Mosman has been strong, especially in the run-up to Easter.

"Mosman's annual growth has been consistent over a long period of time. supply increased in March, but clearance rates also remained steady. This has boosted the confidence of buyers and sellers alike."

Records show that the duplex last traded in 2007 for $1.6 million.

In Pyrmont, the one-bedroom flat at 51/56 Pirrama Road in Sydney Wharf sold for $2.76 million.

Two owner-occupiers, a Perth buyer seeking a Sydney haven and a North Shore family looking for an urban base with boat mooring, registered bids for the waterfront home.

The opening bid was $2.5 million, below the $2.6 million guide, and bids climbed mainly in $50,000 increments as the three bidders competed. The winning bid was from the North Shore family.

Adrian Wilson, a sales agent from Ayre Real Estate, declined to disclose the reserve price, but said the sellers - a retired couple who were giving up their investment property - were pleased with the outcome.

Wilson said there was still a strong interest in prestigious properties and those in good locations, especially for those downsizing.

Records show that the home last traded in 2010 for $1.085 million.

Dr Shane Oliver, chief economist at AMP Capital, said Saturday's auction sale rate was up on the previous week, reflecting a seasonal uptick ahead of the canteen break and cooler months.

Oliver said lower listings and sales volumes also supported buyer demand. However, he expects results to loosen as high mortgage rates reduce buyers' spending power.

"The overall picture suggests that buyer demand is solid, but not booming, in a limited housing stock. Hopes of a topping out of interest rates, a tight rental market and returning immigrants hunting for lower prices are supporting the market."

The most expensive deal on Saturday was a reported $11.8 million paid for a six-bedroom, six-bathroom Dover Heights home, which sold for $800,000 above the reserve price. The home had a guide price of $9.5 million.

Bidding for 54 Gilbert Street began at $8.8 million and there were 32 bids in 45 minutes. Three of the five registered bidders made offers on the house, which has a roof overlooking the Harbour Bridge.

The house was sold through Monika Tu of Black Diamondz Property Concierge to a local Australian entrepreneur who was represented by the buyer's agent. The two lower bidders were from China.

Tu said the additional stamp duty levied on international buyers limited the amount they were prepared to spend on the home.

"The extra eight per cent stamp duty really stopped them from buying. Fortunately, ...... There have been a lot of permanent residence visas approved [recently], so we have a lot of [international] buyers now."

Records show that the home last traded in 2011 for $4.9 million.

In Dolls Point, a first-time buyer couple from Botany purchased a two-bedroom villa for $1.03 million.

Eight people registered to bid for 5/122 Russell Avenue and five buyers took an active part in the auction.

The bidders included small business owners, investors and other first-time buyers.

The home was sold by Mitch Kenyon of McGrath Cronulla.