It could take years to know the full impact of the decision to stop refining oil at Whangarei's Marsden Point

The oil refinery will convert into a fuel-import-only terminal from April.

Refining NZ shareholders voted overwhelmingly for the change, due to the glut of global fuel supplies, high pipeline fees, and plummeting fuel demand.

But JMI Wealth Director Andrew Kelleher says it will mean the loss of hundreds of jobs at the refinery itself -- and hundreds more at contractor companies.

There are many contractors and suppliers with skilled workers that are reasonably dependent on the refinery.