Motorists on State Highway 88 between Dunedin and Port Chalmers are being asked to remain patient while Delta clears vegetation away from power lines.
Contractors started clearing macrocarpa trees from parts of SH88 road reserve last Tuesday and planned to finish on Wednesday, weather permitting.
Delta asset management general manager Adam Fletcher said the work was part of Aurora Energy's overhead line renewal programme and would improve electricity supply reliability.
''Trees growing near power lines can cause damage and interrupt power supply. Clearing vegetation from the roadside will also improve driver visibility,'' he said.
The wood was being donated to a Lions group.
At times, the highway had been reduced to a single lane.
Mr Fletcher said contractors appreciated motorists' patience.
Earlier in the week, the Dunedin City Council encouraged cruise ship tour operators to allow extra time on tours or take alternative routes including Upper Junction Rd.