A "No 8 wire attitude" and "ballsy" decision-making saved NZ Steel up to $120 million after a catastrophic failure recently shut down production at its Glenbrook plant.

With too few spares and its Norwegian supplier closed, NZ Steel faced the prospect its 24-hour plant could lie idle for as long as six weeks.

The mill was in dire straits, until do-it-yourself New Zealand technology came to the rescue.

On July 19, the water cooling system at the South Auckland plant sprung a leak, leaving anodes used to make steel and their surrounding components unprotected.

"There was actually nothing in the (water) pipe so it just sent up hot gasses and air and that completely melted all of the rubber componentry," said Dean Adams, at the time acting procurement manager for just two days.

It was not until the next day staff managed to get in and discover the full extent of the damage, he told NZPA.

"We carried recommended spares for one anode, but there's actually eight and we melted the rubber componentry for all eight. We had 12 (spare parts) but we needed 72. It was massive," he said.

A call to their parts supplier in Norway yielded more bad news.

The factory was closed and no new parts would be available for up to six weeks, the Norwegians said.

The parts had been expected to last up to 25 years, so the Norwegians did not keep spares lying around.

"When you are losing $100,000 to $150,000 for every hour you are down (in a plant which normally runs 24 hours a day), it doesn't take much for the shareholders to be affected in a negative way," Mr Adams said.

" It was a catastrophic failure because we didn't have the parts available to make the plant operable again."

Mr Adams started looking for local solutions.

NZ Steel enlisted 30 New Zealand companies to design, manufacture and install the parts required, the biggest job going to Skellerup who became the lead company tasked with making the rubber components from scratch.

"The Norwegians said, `You are wasting your time. These are special moulds made with special tolerances and the rubber componentry has an intellectual property component that says only we know what the recipe for the rubber is.

"And they wouldn't share that with us so we had to work out what components were made of as best we could," Mr Adams said.

Chemists from three rubber makers were asked to submit compound ideas and all of them reached the same conclusion.

While Mr Adams said it was a "ballsy" move for NZ Steel to commit large sums of cash to finding a solution, but "it wasn't a leap of blind faith".

NZ Steel did a lot of hasty risk assessment work and were confident the job could be done.

"If we had failed then we don't know what the result would have been," he said.

At worst, it could have financially crippled NZ Steel.

As the company commissioned multiple moulds for components, Mr Adams was glued to the phone seeking alternative parts from overseas.

In the end the New Zealand parts fitted and worked first time.

"It was done in nine days, a remarkable feat," Mr Adams told The Shed magazine.

"It's the No 8 wire attitude. After Norway said it can't be done, New Zealand said `well we don't accept that so we're going to do it anyway'.

"If we lose a big industry like NZ Steel then you don't have to speculate too much on what the effect on the economy is."

The New Zealand-made parts were still in use and NZ Steel now had plenty left over.