New Zealand's state-owned electricity transmission network operator Transpower has clarified its grid upgrade proposals, after a speculative media statement caused some misunderstanding.

Transpower said that a claim being made by the Homeowners Against Line Trespassers (HALT) group, stating that the company’s amended North Island grid upgrade proposal includes building two lines from Whakamaru to South Auckland, is incorrect.

The company clarified that its proposal is, in fact, to build a single 400kV overhead transmission line from Whakamaru to South Auckland, which will initially operate at 220kV, and will only be upgraded to 400kV when needed.

Transpower said that HALT’s claims were based on an option to build two lines that was previously suggested by the region’s Electricity Commission as a possible alternative to building the 400kV transmission line.

Transpower added that, as part of the upgrade, a transition station will be built at Brownhill Road, and a 220kV underground cable will run to the Pakuranga substation. At a future date, a second 220kV underground cable may be run from Brownhill Road to the Otahuhu substation.

Tranpower said that the commission target for its upgrade work is 2011.