Frasers Centrepoint Limited (FCL) trumped nine other bidders with an offer of $955.4 million for a residential plot in Jiak Kim Street, the former site of popular nightspot Zouk.
And Allgreen Holdings emerged top among seven bidders for a residential parcel in Fourth Avenue, lodging a tender of $552.96 million.
The two 99-year leasehold sites were on the Reserve List of the Government Land Sales programme and were triggered for public tender after minimum acceptable bids were made.
The 13,482 sq m site in Jiak Kim Street comes with commercial use on the first floor. FCL's bid for the site translates to $1,732.55 per sq ft per plot ratio (psf ppr), only 0.6 per cent above the bid from Hong Leong Holdings and Hong Realty, which are controlled by Singapore tycoon Kwek Leng Beng.
This toppled the last high of $1,239 psf ppr achieved at the site for GuocoLand's Martin Modern in June last year by a stark 39.9 per cent.
The $552.96 million bid by fellow tycoon Robert Kuok's Allgreen Holdings for the 18,532.2 sq m site in Fourth Avenue reflects a land rate of $1,540 psf ppr, which is 2 per cent above the second-highest bid, from Bukit Sembawang Estates.
Allgreen Properties picked up two collective sale sites in Bukit Timah last week, including Royalville.
The bullish bids come after warnings from the Government on over-exuberance in the property market.
"Despite the authority flagging the risk of excessive exuberance... the bidding for choice sites has not shown any sign of slowing," said Cushman & Wakefield research director Christine Li.
Ms Tricia Song, research head for Singapore at Colliers International, said the strong showings for the Jiak Kim Street and Fourth Avenue sites "clearly reflect bidders' confidence in a recovering... market amid the positive economic outlook".
Frasers Centrepoint Singapore chief executive Christopher Tang said the Jiak Kim Street site is "a rare location in a cosmopolitan locale, filled with rich heritage and character, sitting right on the edge of the Singapore River".
Market watchers felt that the aggressive price Allgreen paid for Royalville could have deterred some developers from bidding for the site in Fourth Avenue. Still, having seven bidders is considered a respectable showing, Ms Li said.
JLL head of research and consultancy Tay Huey Ying noted that the batching of tender closings for the two sites "appeared to have helped spread the competition for each site, and potentially taming the bids somewhat".
She added: "Interestingly, local developers continue to maintain their hold on the prime district market, pipping foreign developers such as China's CSC Land and Hong Kong tycoon Li Ka-shing's Japura for the two sites in Jiak Kim Street and Fourth Avenue, respectively."