Casa Sophia in District 9 is up for collective sale with a reserve price of $36 million.

Owners at the freehold, 12-unit development in Mount Sophia could receive between $2.69 million and $3.4 million.

"All owners are very supportive and we are happy to have garnered 100 per cent consensus. The location is surrounded by prestigious schools and is close to the heart of Orchard Road. Projects here will definitely appeal to both investors and families," ERA representative Tjhai Citanegara said.

Based on the reserve price, the land rate translates to an estimated $1,390 per sq ft per plot ratio (psf ppr), excluding development charge.

Under the Urban Redevelopment Authority's Master Plan 2014, the site is zoned residential with a gross plot ratio of 2.1.

It could be rebuilt into an estimated 34 units, based on a 753 sq ft per unit size.

The tender closes on Aug 14.

Separately, the four-storey, 24-unit Haig Road Flats is up for collective sale. Century 21 marketing agent C.S. Chong said the expected market price is between $51 million and $52 million - netting each owner $2.1 million to $2.2 million.

Development charge and related costs of about $2.87 million could be levied, he added.

The land rate translates to just a tad above $1,300 psf ppr. The 999-year-lease apartments are located close to the upcoming Marine Parade MRT.

It has a site area of 27,389 sq ft and is zoned residential with a gross plot ratio of 1.4.

It can be developed up to five-storeys high with 35 units.

The tender closes on Aug 7.