As a number of prime sites get vacated, the authorities are working out what use they should be put to.
For example, it was announced last month that the Central Manpower Base (CMPB) is moving out of Depot Road to Upper Bukit Timah.
The Ministry of Defence (Mindef) will continue to have a presence at the site as the Defence Science and Technology Agency (DSTA) will remain at the Depot Road camp.
Meanwhile, plans for the site after CMPB moves out are being finalised.
In the long term, based on the Urban Redevelopment Authority's (URA) Land Use Plan 2030, the 60,300 sq m site is zoned for residential use. But for the next 10 to 15 years, it is zoned for a civic and community institution, according to the URA's Master Plan 2014.
Other prime sites have also not yet realised their long-term fate.
For some, including Tanglin Village in Dempsey Road, the former Ministry of Education headquarters in Kay Siang Road, and the former Raffles Institution (RI) in Grange Road, there are no immediate plans to redevelop them, a URA spokesman said.
Instead of leaving these properties vacant, the Singapore Land Authority (SLA), URA and other agencies work together to "determine the allowable interim uses, tenure and technical requirements", an SLA spokesman said.
There are also no immediate plans to redevelop Wessex Estate, which is meant for residential use in the long term and has been incorporated into the one-north development, for which JTC Corporation is the master-planner and developer.
The 26 blocks of walk-up apartments and 58 semi-detached houses are on one-year tenancies, a JTC spokesman said. A few blocks have been converted into work lofts for creative and fine arts workers. The 30ha former British army base is marked out as "subject to detailed planning" in the Master Plan 2014.
The four sites slated for long-term residential development - Tanglin Village, 1 Kay Siang Road, CMPB and Wessex - could yield about 1,900 to 2,400 homes, said R'ST Research director Ong Kah Seng. The CMPB site could yield about 700 condominium units, he estimated.
The 55,800 sq m former RI at 51 Grange Road - now the Ministry of Education's Teachers' Network - is zoned for an educational institution in the long term.
Should these parcels be sold, they would likely be on a tenure of 99 years or less given the scarcity of land here, said Chestertons research head Elaine Chow.
The 40ha Tanglin Village is listed as a reserve site in the Master Plan 2014, as is the roughly 96,200 sq m Kay Siang site.
Tanglin Village was once barracks for British soldiers, and later the headquarters of Mindef, CMPB, and the Civil Service Club. The area's interim use is as a "lifestyle hub" with food and beverage and retail options, the URA said.
"The five sites have good development and redevelopment potential, and their quality environment can allow some to incorporate interesting mixed-use concepts," said Mr Ong.
"But plans for developing these residential areas are likely to be firmed up only after the Government has fully tackled housing needs for the masses (in such suburban locations as Bidadari, Tampines North and Punggol Matilda)... Buyers' interest for high-end homes has also eased over the years, so there is no need to stress (the market) with the redevelopment of these clusters."