Milford Sound's harbour is to have a $6 million upgrade including a rebuilding of the 22-year-old man-made breakwater, starting next month.
The Milford Sound Development Authority (MDA) has been given approval by the Department of Conservation and Environment Southland to extend the harbour basin a further 10m from shore.
MDA is a private company responsible for the harbour's facilities and infrastructure. The Skeggs group owns 49 per cent, Real Journeys 49 per cent and the Southland District Council 2 per cent.
Board chairman Jeff Grant said the purpose of the upgrade was primarily based around Maritime New Zealand safety concerns and improving harbour efficiency.
Concerns included overcrowding on the wharf during the peak season of November-February and boats having to moor in deep water overnight because of of a lack of berths.