Flat Bush (also known as Ormiston or Flatbush) is a southeastern suburb in the city of Auckland, New Zealand.

It has recently become one of the city's largest new planned towns after being developed as an urban area of Auckland for several decades.

Located east of Ōtara, plans for substantial expansion began under the Manukau City Council — having bought 290 hectares in the area in 1996.

[5][6] Over time, Ngāi Tai formed unions with many Tāmaki Māori groups in the area, including Waiohua and Ngāti Pāoa.

[7] During the Musket Wars in the 1820s, Ngāi Tai Ki Tāmaki sought temporary refuge in the Waikato.

[11] In 1854 when Fairburn's purchase was investigated by the New Zealand Land Commission, a Ngāi Tai reserve was created around the Wairoa River and Umupuia areas, and as a part of the agreement, members of Ngāi Tai agreed to leave their traditional settlements to the west.

[12][13] In 1847, Howick was established as a defensive outpost for Auckland, by fencibles (retired British Army soldiers) and their families.

[16] The wider East Tāmaki area was settled primarily by Scottish and Irish Presbyterian settlers.

[20] In 1921, the East Tāmaki Co-operative Dairy Company was formed, producing milk and butter for the wider Auckland area.

[7] The Manukau City Council identified Flat Bush as a crucial site for future urban development in the 1970.

[21][22] In 1997, the Manukau City Council drafted a development plan for Flat Bush,[23] with the first construction beginning in 1998 in the Chapel Park subdivision.

[24] Swathes of new residential subdivisions were dubbed Ormiston in the mid-2000s, due to Botany Community Board concerns around associating with Ōtara (a socioeconomically deprived and ethnically diverse part of the city).

[29][30] The suburb contains the 94-hectare Barry Curtis Park, named in recognition of Manukau's longest standing mayor, Barry Curtis,[31] The suburb's new shopping centre, Ormiston Town Centre, was officially opened to the public on 25 March 2021.