Maritime Union of New Zealand national secretary Craig Harrison says it is naive to think that oil companies involved had any commitment to New Zealand other than ensuring profit.
"Their interest is shareholder return. New Zealand's interest is energy security. These two interests are in conflict with each other," he said
The recent buy out of Z Energy by Ampol shows any local control of fuel has been completely lost, Harrison said.
He said the current global supply chain crisis is a red alert warning that New Zealand needed to have a strategy for secure energy supplies.
Political tensions in the Asia-Pacific region were another emerging threat to reliance on Asian refineries.
Harrison said New Zealand can't rely on the good will of global fuel companies and drew an analogy with what has happened in shipping services to New Zealand in the last year.
"Previous governments forced us into reliance on global shipping companies to move New Zealand exports and imports, and there was no backup plan."
Harrison said the Government needs to move to keep Marsden Pt open to ensure New Zealand fuel security, as well as ensuring New Zealand flagged coastal tankers remained in service.
Energy Minister Megan Woods said a number of parties have approached the Government with proposals for the refinery's future and views on fuel security, and the possible future uses of the site.
She said the Government continued to keep an open mind about the planned closure of the refinery and potential future uses for the site, including green fuels. She said the Government was considering options to promote fuel supply security in a situation with no domestic refining, including the fuel stockholding policies.
Meanwhile, a petition that has already garnered more than 17,000 signatures calling on the Government to help save the Marsden Pt oil refinery from shutting down could be one of the largest signed on an online platform.
Whangārei-based Chris Leitch of the Social Credit Party last month started the petition on change.org, calling on the Government to declare the refinery a nationally strategic asset and to compulsorily buy all the shares from private owners using money created by the Reserve Bank.
The Government, he said, should then turn it back into a state-owned enterprise and allow fuel retailers, rather than a monopoly consisting of major oil companies as is the case at present, to sell fuel in the country.
While we need to transition away from reliance on fossil fuels the decision to shut down the refining operation at Marsden Pt has been made by the shareholders purely in the interests of generating larger profits from imported refined product and not in the interests of New Zealand's strategic fuel needs, Leitch said.
''This decision means we will still be burning the same amount of fuel, but become even more reliant on imported products from overseas owned conglomerates,'' he said.