The Marsden Point oil refinery is marking its 50th anniversary with indications it may broaden its shareholder base to help ensure greater financial and strategic stability.
The refinery supplies around 80% of the country's refined fuels. It is located just south of Whangarei and owned by the New Zealand Refining Company.
Oil companies hold 73% percent of the company.
Shell sold its 17% stake to Infratil and the New Zealand Superannuation Fund in April 2010.
Chief executive Ken Rivers says that while shares have been tightly held in the past, that may change as the current owners review their positions with a view to selling down their shares.
He says if shares do become available he wants to be sure potential investors understand that New Zealand Refining is an attractive company to have a shareholding in, as well as an attractive company to have as a neighbour and as a supplier.
Mr Rivers says fears about slowing global growth and falling Singaporean refinery margins should not greatly affect the refinery's prospects since it produces high-value products and is close to its market.
He says studies have shown that historically it outperforms Australian refineries and stands with the best in Asia.
He says the company is also protected because any slackening in the market is absorbed in a reduction in imports rather than in a cut in the company's output.