Investors have heartily backed a $365 million upgrade to New Zealand's only oil refinery - but the petrol giants that own most of the company did not show the same solidarity.

Refining NZ chief executive Ken Rivers, who was "over the moon" at the decision, was biting his nails at yesterday's annual meeting.

The board had already approved the project in February, but the sheer size of the investment required majority shareholder support to get the final sign-off.

After auditor PwC completed the official vote count, the final tally was 64.5 per cent in favour and 35.5 per cent against.

For Rivers and his senior management team that meant the past two weeks of wooing shareholders here in New Zealand and around the world had paid off.

Non-oil company shareholders holding 17 per cent of the company passed the resolution with an overwhelming 99.8 per cent majority. "I just can't say how grateful I am for their support," a jubilant Rivers said.

But cornerstone investors and customers Chevron, Z Energy, Mobil and BP, collectively owning 73 per cent of the company, were divided on the issue.

BP and Z Energy confirmed they had voted for the project but voting numbers released by NZ Refining indicated Chevron and Mobil had voted against.

Rivers said it was interesting that others had turned down the "compelling case", but accepted it may not have been in their strategic interests.

"I've got to recognise that some of my customers who are also shareholders, are also my competitors, who are investing in similar projects," he said.

"Clearly, for some, it wasn't as palatable as their alternatives."

The successful vote means construction of the Continuous Catalyst Regeneration (CCR) platformer, to be installed at Marsden Point, will kick off in 2014. It also means the back-up $105m "Re- Life" plan, which would have extended the life of the existing platformer, will be scrapped.

Once up and running, the CCR investment is expected to hike operating earnings by $60m, and increase shareholder dividends by 30 per cent.

The CCR project allows a wider range of crudes to be processed more efficiently, with energy- efficiency measures accounting for 70 per cent of the value.

It is also expected to boost the Northland economy through the creation of 300 new jobs, with twice as many again created in supporting industries nationwide.

However, Rivers will return to Britain before the year is out, and the company is already on the hunt for a replacement.

Rivers said his shareholding in Refining NZ, which he was about to increase, would keep him tied to the company, and to New Zealand.

NZ Refining shares were placed in a trading halt for most of the day pending the announcement, but rose 3.64 per cent to $2.85 by the market close. Fairfax NZ

Copyright 2012 Nelson Evening Mail Limited. All Rights Reserved.

(Originally published April 28, 2012, in The Nelson Mail.)