Transpower has been given approval to recover the cost of increased capital expenditure, to secure designations and property rights for two switching stations in the upper South Island.

The Commerce Commission has approved a rise in investment from five million to eight million dollars.

It's for Transpower's preferred options to built the switching stations between the Orari and Rangitata rivers near Geraldine in South Canterbury.

Commission Deputy Chair Sue Begg says there's a risk of changing land use in the area from mainly pastoral and crop farming, to intensive dairy farming.

She says this move provides certainty for landowners and for the cost of future construction, which benefits consumers.