Its predecessor was the Porirua Borough Council, formed in 1961 when the population of areas north of Tawa Flat was becoming so substantial that the Makara County was renamed as a more urban body and its rural south became the Makara Riding of the adjoining Hutt County, which was still predominantly rural.
By 1965 it was clear that the population of Porirua Borough had exceeded the magic 20,000 that was then the minimum for "city" status. Representations were made, and in due course Porirua was proclaimed to be a city. It extended to Titahi Bay in the north-west and Cannons Creek in the east, with more state housing planned for the east and at least one substantial private subdivision at Papakowhai in the north-east, next to the Hutt County's growing settlement of Paremata.
The council was enlarged on 1 April 1973 with the addition of two urbanised ridings of the Hutt County (Plimmerton-Paremata and Pukerua Bay) and parts of the Makara Riding (the rest of which went to Wellington City).
A further major enlargement occurred late in 1988 with the addition of the Horokiri Riding of the Hutt County (including most of the large Whitby suburb), as the county was being dissolved because all of its ridings had substantial urban cores and were to become independent boroughs or merge with an adjoining city. Porirua survived the 1989 shakeup of local government and remains a proudly independent city into the 21st century.
|Territorial Authority Districts of New Zealand|
|Auckland | Hamilton | Tauranga | Napier | Palmerston North | Porirua | Upper Hutt | Lower Hutt | Wellington | Nelson* | Christchurch | Dunedin | Invercargill|
|North Island: Far North | Whangarei | Kaipara | Thames-Coromandel | Hauraki | Waikato | Matamata-Piako | Waipa | South Waikato | Otorohanga | Rotorua | Waitomo | Taupo | Western Bay of Plenty | Whakatane | Kawerau| Opotiki | Gisborne* | Wairoa | Hastings | Central Hawke's Bay | New Plymouth | Stratford | South Taranaki | Ruapehu | Wanganui | Rangitikei | Manawatu | Tararua | Horowhenua | Kapiti Coast | Masterton | Carterton | South Wairarapa|
|South Island: Tasman* | Marlborough* | Buller | Grey | Westland | Kaikoura | Hurunui | Waimakariri | Selwyn | Ashburton | Timaru | Mackenzie | Waimate | Waitaki | Queenstown-Lakes | Central Otago | Clutha | Gore | Southland|
|Territory: Chatham Islands|