A Mosman housing proposal covering 10 properties across Ourimbah Road and Heydon Street has been declared State Significant Development following a recommendation from the Housing Delivery Authority (HDA).
The proposal covers 1, 3, 5, 7, 9, 11, 13 and 15 Ourimbah Road and 10 and 12 Heydon Street and has an indicative yield of about 120 dwellings. HDA reporting describes the project as a residential flat building with 5 per cent of the dwellings dedicated to affordable housing in perpetuity.
The signed ministerial order also identifies the Mosman land among the latest developments formally declared State Significant. SSD status allows the proposal to proceed through the state assessment pathway but does not amount to development approval.
Ten properties form the proposed development site
The development footprint takes in eight consecutive Ourimbah Road addresses and two properties on Heydon Street.
The project is recorded as EOI 373897 and was among 10 proposals recommended by the Housing Delivery Authority at its August 18 meeting. The NSW Government’s HDA register subsequently recorded the proposal as declared State Significant Development by the Minister.
HDA material reviewed for the declaration does not specify the final building height, apartment mix, parking provision or site-access arrangements. More detailed plans would be expected as the project progresses through the State Significant Development assessment process.
Separate Ourimbah Road project draws 57 submissions
A separate State Significant Development application is also progressing at 40-56 Ourimbah Road, where plans propose demolition of existing dwellings and construction of a part eight-, part nine-storey residential flat building containing 63 apartments.
Mosman Council says the development includes 12 in-fill affordable housing apartments, two basement levels and parking for 92 cars, with vehicle access from Ourimbah Road. The application was publicly exhibited from July 23 to August 5.
The NSW Planning Portal records 57 submissions and lists the project at the Response to Submissions stage. Published objections raise concerns including height, bulk, traffic, excavation, heritage impacts and vehicle access, while published submissions also include support for the proposal and its approach to design, setbacks, landscaping and solar access.
Mosman Council lodged its own objection to the 40-56 Ourimbah Road application. Council records state the applicant is preparing a response to submissions, with the State Government listed as the determination authority.
Detailed assessment still to come
The newly declared 1-15 Ourimbah Road and 10-12 Heydon Street proposal is at an earlier stage than the separate development at 40-56 Ourimbah Road, which has already progressed through public exhibition.
State Significant Development declaration enables the 120-dwelling proposal to proceed through the NSW assessment pathway used for projects recommended by the Housing Delivery Authority. A development application would still need to undergo detailed assessment and public exhibition before a determination is made.
Published 25-Aug-2026
