Contractors in helicopters will pour 80 tonnes of gravel on to a total of 917m of track on Harris Basin, between Harris Saddle and the Falls hut in late spring.
The project began last year.
Doc Wakatipu area office capital works project manager Richard Struthers said the work was scheduled for early in the season when the track was often closed because of avalanche risk.
"The Routeburn has been upgraded in sections many times but this section hasn't been touched for 30 years. It's one of the most difficult sections because it's alpine.
"It has a lot of bedrock and is subject to severe snow and rainfall. The uphill batter of the track will not be disturbed and there will be no removal of alpine vegetation, which takes decades to grow."
The Doc contractor would partially realign sections of track totalling 95m which were uneven or eroded and did not meet the standards of a Great Walk, Mr Struthers said.
About 30m of boardwalk had been laid and the project would be completed by the end of October, depending on weather conditions.
Elsewhere in the Wakatipu, the office's summer schedule will allow the public to enjoy the Kawarau rapids from a new viewing platform at Roaring Meg.
The unsheltered 4.5m-diameter platform was expected to be made from concrete, wood and steel, and would have information panels installed.
The proposal followed the completion of a 30-vehicle parking area and single-lane access off State Highway 6 by Transit New Zealand.
Tenders would be sent out this month and construction was to start and finish before Christmas, Mr Struthers said.
A new swing-bridge was planned across the lower Snowy River, near the Dart hut on the Rees-Dart Track.
An upgrade of the existing campsite shelter and toilet was also planned for autumn next year.
Department staff would fill bogs, install culverts and metal the trail on the Mt Crichton Loop Track over winter.
Historic miners' huts at the Whakaari Conservation Area in the Buckler Burn catchment were tipped for restoration. The Jean hut would have repairs to the floor, drains and windows.
McIntyres hut would be converted into accommodation for five people, and the beech pole and corrugated-iron-clad Wallers hut was to be fixed.
Two teams of five would return to work on the Skippers school house and homestead as part of a five-day conservation volunteer project in February next year.
The house dated back to the early 20th century.
Restoration was carried out by Doc 15 years ago and it was due for maintenance, Mr Struthers said.
