<P> In 1981, the expansion began and the government approving a 170 kilometres (110 mi) pipeline to Wiri, south Auckland . A workforce of 5,000 worked on the expansion, which was by now expected to cost $1.55 billion . Strikes during the project led to the introduction of the Refinery Expansion Projects Dispute Act by the Muldoon government . An inquiry into the strikes and the governments' reactions to them followed . In 1985, the refinery shut down for five months for maintenance work on the old refinery . The project was completed in 1986, two years behind schedule and at a final cost of $1.84 billion . During this time, the price of oil fell to $8 US per barrel and the refinery was mothballed . It was cheaper to import refined petroleum than it was to process it at Marsden Point . </P> <P> Following the election of the reformist Fourth Labour Government in 1984, the Petroleum Sector Reform Act was introduced . This Act deregulated the petroleum industry, with 1,500 workers expected to lose their jobs . The Refinery assets were transferred by the Government to the New Zealand Refining Company Limited, a consortium of the five major petrol retailers . BP, Mobil and Z Energy are currently major shareholders . The Government injected $80 million to enable the company to adapt to the new environment . A major efficiency drive was launched to cut operating costs . </P> <P> The refinery uses a medium - sour blend of crude oil, nearly all of which is imported . Most crude oil produced in New Zealand is light - sweet and is exported to refineries in Australia . Marsden Point produces 70 per cent of New Zealand's refined oil needs, with the rest being imported from Singapore, Australia and South Korea . </P> <P> A 168 kilometer (104 mile) underground pipeline connects the refinery to the Wiri Oil Terminal in Auckland . The pipeline is 25 centimeters (10 inches) in diameter and transports petrol, diesel and jet fuel at up to 400,000 litres (105,669 US gallons) per hour . Supply was halted for pipeline repairs in September 2017 after an excavator damaged the pipeline on a rural property near Ruakaka, leading to jet fuel shortages and flight cancellations at Auckland Airport . </P>

How does the marsden point to wiri pipeline work