The cost of fixing Rotorua's ailing lakes could be as high as $100 million, says a senior regional council official.
Rotorua Lakes Protection and Restoration Action programme co-ordinator Paul Dell said the $100 million figure was a ballpark indication of the cost the region might face.
It would include engineering options forthe lakes as well as the major cost of land use changes.
A Cabinet paper dealing with the situation of Lakes Rotoiti, Rotorua and smaller lakes had been drawn up for the Government.
Mr Dell hoped the Government would match the contribution it is making to clean up Lake Taupo.
The fix-it bill for Lake Taupo has been calculated at more than $81 million over 15 years, with about $18 million coming from Taupo District Council ratepayers.
The Government has pledged nearly $37 million, leaving Environment Waikato to pay almost $27 million.
Mr Dell said the complexity of the problems with Lakes Rotoiti and Rotorua, linked by the Ohau Channel, meant it could take more than three years to develop a fully integrated plan.
But more urgent work needed to be completed within that time.
Water from Lake Rotorua is responsible for more than 70 per cent of Lake Rotoiti's nutrient load, which feeds algal growth and decreases water quality.
