The Manukau City Council says it will fight to see transmission lines proposed by Transpower undergrounded from the Bombay Hills to Otahuhu.
On Tuesday, Transpower started sending letters to affected landowners along the proposed 400kV route, which stretches from Whakamaru in the Waikato to Otahuhu in South Auckland.
The letterstold the landowners where their properties sit in relation to the 500m-wide path for the line, which will be strung on 490 towers, some up to 70m high.
Transpower has said it will underground the line the last 7km to Otahuhu. Manukau Mayor Sir Barry Curtis says the plan is outdated and unacceptable.
He said the lines should be put underground from the Bombay Hills, adding a further 30km of undergrounding.
The council would lodge an appeal when Transpower sought planning consents for the route next year.
"It's not too late to stop Transpower's plan," said Sir Barry.
"I feel very strongly about this issue and the council is committed to doing its best to stop the plan going ahead."
He said the council did not want to block planning for the upgrade, which will secure Auckland's power supply, but the proposal was unacceptable as it stood.
Sir Barry said the plan would see a string of 50m- to 65m-high pylons crossing Clevedon, south of Auckland city, which was densely settled, and the line would also cross near Ardmore aerodrome.
Transpower spokesman Chris Roberts said it had decided on undergrounding the final 7km of the line into the Otahuhu substation.
Transpower had looked at the Auckland Regional Growth Strategy and, based on that, undergrounding from 7km out would cover any possible urban development in the area until 2050.
