Tangiwai is a and a small rural community in the Ruapehu District of the Manawatū-Whanganui region of New Zealand's North Island. It is located east of Ohakune and Rangataua and west of Waiouru on State Highway 49. In 2018, 37.5% of the area's 1,281 residents worked in agriculture, forestry and fishing and 7.1% in manufacturing.
The New Zealand Ministry for Culture and Heritage gives a translation of "weeping water" for .
New Zealand's worst rail accident, the Tangiwai disaster, occurred near Tangiwai on 24 December 1953. The Whangaehu River rail bridge collapsed beneath a Wellington-to-Auckland express passenger train. The locomotive and first six carriages derailed into the river, killing 151 people. The subsequent Board of Inquiry found that the accident was caused by the collapse of the tephra dam holding back nearby Mount Ruapehu's crater lake, creating a large lahar in the Whangaehu River, which destroyed one of the bridge piers at Tangiwai only minutes before the train reached the bridge. A memorial has been built at the accident site.
Tirorangi Marae and Rangiteauria meeting house is located in the Tangiwai area. It is a traditional meeting ground of the Ngāti Rangi hapū of Ngāti Rangihaereroa, Ngāti Rangiteauria and Ngāti Tongaiti.
Demographics
Tangiwai statistical area, which includes Rangataua and which surrounds but does not include Raetihi, Ohakune and Waiouru, covers . It had an estimated population of as of with a population density of people per km<sup>2</sup>.
The statistical area had a population of 1,449 in the 2023 New Zealand census, an increase of 168 people (13.1%) since the 2018 census, and an increase of 222 people (18.1%) since the 2013 census. There were 786 males, 660 females, and 3 people of other genders in 627 dwellings. 1.4% of people identified as LGBTIQ+. The median age was 41.2 years (compared with 38.1 years nationally). There were 300 people (20.7%) aged under 15 years, 210 (14.5%) aged 15 to 29, 696 (48.0%) aged 30 to 64, and 240 (16.6%) aged 65 or older.
Timber
thumb|300x300px|Tangiwai in 2011, showing pulp mill to west and timber mill and forest to the north of the railway
George Syme & Co ran a saw mill to cut totara, rimu, matai and kahikatea, linked to the station by a tramway from 1908 until 1930. The mill burnt down in 1926.
Karioi state forest was set up in November 1926, with set aside for forestry, and taken on by New Zealand Forest Service from 31 March 1927. By March 1931, over 10.7m trees had been planted on , for £56,524, 15s 10d. Most of the planting was on land with cobalt deficiency and therefore considered unsuitable for farming, though it also included at least of flax. Trees have been harvested since the late 1960s. Winstone Pulp International (WPI) bought of Waimarino Forest in 1989 and cutting rights to of Karioi Forest in 1990.
Sawmill
To cut the timber, MSD Spiers built Tangiwai Sawmill beside the railway station in 1966. It was bought by nearby pulp mill owner, Winstone Pulp International Ltd (WPI), in 1993 WPI employed about 300 staff. At 30 September 2006, its forest crop was valued at $83m and its fixed assets at $38.7m. It earned $131m, but lost $10.1m. Ernslaw One also has forests and mills in Gisborne, Naseby and Tapanui.
Pulp mill
A further use for the timber was the pulp mill, though it had a troubled beginning. It produces a year when running a single-shift. It is mainly used for newsprint and paperboard, much of it exported then CentrePort Wellington A bark furnace and a heat exchanger recover of heat from steam for drying the pulp, electricity and LPG supplying the other energy. Excess heat is used to dry timber from the sawmill. In 2004 the mill had 145 staff.
In 1976 Winstone and Chonju Paper Manufacturing, a Samsung subsidiary, built a thermo-mechanical pulp mill, almost north of the sawmill. In 1978 the first load of logs was delivered to the mill. At least 70% of the pulp was to go to Chonju, but, when the mill came on stream in 1979, prices for pulp and newspaper had fallen and the pulp was of variable quality. In 1981 the mill was caught up in the Think Big debate, On 10 September 2024, the company confirmed that it would close down its Karioi pulp mill and Tangiwai timber mill by October 2024, leading to the loss of 230 jobs. WPI chief executive Mike Ryan attributed the closure to the "dual impact" of "uncompetitive" energy prices in New Zealand and the relatively low current and forecast mark prices for pulp and timber." Ryan confirmed that WPI would support staff by helping them to find jobs with other industry players, work with the Ministry of Social Development and Inland Revenue Department to support retrenched staff and provide access to wellbeing providers and financial advisers. On 5 August, the company had also temporarily paused operations at both Karioi and Tangiwai, citing high energy prices.
First Union and E tū issued a joint statement describing the mills' closure as "devastating." First Union general secretary Dennis Maga thanked the local mayors and Associate Energy Minister Shane Jones for fighting to keep the mills open but criticised the Government for not intervening to address the impact of its previous energy reforms.