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Torrential rain may have battered much of the country recently but it seems it's too little too late for NZ's hydro lakes.
And as the chilly winter months draw closer, the public is being asked to cut back to avoid cut offs as security of supply going into winter remains a significant concern.
The announcement follows concern from major industrial electricity users that the power system will struggle to meet peak demand, and warnings by some analysts of winter blackouts unless electricity is conserved.
Transpower, the national electricity grid operator, says despite recent rain, hydro storage levels remain a significant concern to the industry which is continuing with contingency planning to ensure a secure supply of power this winter.
Hydro lake levels are around 60% of average storage, significantly lower than normal at this time of year, mainly because of severe drought which has resulted in very low inflows into the hydro lakes.
Energy analyst Alistair Price says irrigators and air conditioning plants have increased usage because of the very warm summer.
Transpower chief executive Patrick Strange says action is already being taken by the industry to conserve water and this has seen a number of noticeable changes on the power system - high running of thermal plant in the North Island, greater southbound flow over the Cook Strait link and measures undertaken to relieve the constraints that this has been placing on the transmission system.
"The risks are severe dry in the southern catchments or a major plant failure. For now we're just asking people to be cautious, easy enough to turn the light out as you leave the room, just prudent stuff," Strange says.
Current high spot prices will also encourage large industry customers to conserve electricity, he says.
"All generating companies are also ensuring their own generation plant is fully available where possible and there are no problems with thermal fuel supplies."
The electricity industry has started planning for a public energy awareness and savings campaign to encourage the general public to conserve energy.
Strange says it is important to have the plan in place so it can be implemented quickly if it is needed.
The industry is asking consumers to be careful with their energy use and to switch off any appliances, lights and heating/air conditioning when they are not being used.
Hydro lakes aside, over summer the Stratford power plant was shut down for maintenance and dry summer conditions restricted output from the Huntly thermal power station.
The loss of half of the DC link that carries power between the North and South islands has also put pressure on the national grid.
Transpower is looking to the Manapouri catchment in Fiordland where snow is not so much of an issue but Niwa says it is likely there will be less rain than usual in that area.
Strange says although rain earlier in the week bought the industry a little time, the lake levels are still much lower than the company is comfortable with.
"While the power system can manage with lower than average rainfall over the coming weeks, continuing very dry climatic conditions in the key South Island hydro catchments, or a loss of a major generating plant, while unlikely, would require further contingency measures to be implemented during May."
Contingency measures will escalate should the dry weather continue.
"The generators and retailers are talking to their large customers about reducing their electricity usage should it be needed," Strange says.
Energy Minister David Parker says if drought, particularly in the South Island, was to be prolonged for a month or so then "we might have to look at conservation campaigns but we're not there yet".
Meanwhile on Friday Transpower will lodge its application with the Electricity Commission to upgrade the vital DC link between the North and South but that work will take until about 2012.
