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The Cabinet will today discuss a range of anti-blackout measures - but industry insiders remain confident the lights will stay on this winter.

Energy Minister David Parker will present the raft of options aimed at taking the strain off the South Island's emptying hydro lakes.

The plans include:

* Firing up another 100 megawatt mothballed New Plymouth unit.
* Fast-tracking Kawerau's new geo-thermal plant to open next month - two months ahead of schedule.
* Introducing legislation to allow for the temporary lowering of minimum lake levels.
* Load buy-back being negotiated with major industrial users.

The Cabinet is also expected to complete plans for a voluntary power conservation drive today, although that plan will be launched, if needed, at a later date.

Electricity industry leaders yesterday said there was enough generating capacity in the country to last until rain finally fell - expected to be in late July or August.

Combined with the contingency measures, the country's lights would stay on this winter, they said.

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Transpower chief executive Patrick Strange told the Herald even a major plant failure would be absorbed, with the only real chance of blackouts coming from "the mother of all droughts".

Nothing close to such a drought was predicted, and unlike 1992 - when the country was 84 per cent dependent on hydro power - New Zealand relied on hydro for just 64 per cent of its generation today, he said.

"The chance of ongoing blackouts is basically very, very low. There are hundreds of measures you can take ahead of that."

Prime Minister Helen Clark said last night the Government had had no advice that there was a power emergency, though it was "certainly time to be prudent".

"We want it responsibly managed and we are taking the very best advice we can from the Electricity Commission and from Transpower."

Electricity Commission chairman David Caygill yesterday warned power cuts were a possibility, but were likely to be done through the shutting down of hot water cylinders through the ripple control system.

"It is possible," he said on TVNZ's Agenda programme. "But I think what we should do is be prudent in our use. I think that is what we could do to make sure we avoid involuntary cuts."

Independent energy consultant Bryan Leyland said he expected the country to "just scrape through" this year. But contingency planning should be aimed at a worst-case scenario - which could leave huge blackouts across the country.

If rain did not fall, Auckland would probably be split into about 10 sectors, with each sector having a turn to have its lights go off for about an hour between 4pm and 8pm, he said.

If one of the country's thermal stations had problems - Auckland's Otahuhu B was offline for the past four days and one of Huntly's coal-fired units is overdue for an overhaul - power to hot-water cylinders could be switched off on a rolling schedule as early as next week, he said.

Spot price levels had already forced some industrial power users to scale back production, and more would follow.

But the earlier opening of Mighty River Power's geothermal Kawerau plant would go a huge way to easing the pressure, chief executive Doug Heffernan told the Herald yesterday.