Nearly 30 options have been identified to improve access across the storm-damaged Marlborough Sounds.
Engineering consultancy Stantec is working on a business case on behalf of the Marlborough District Council and Waka Kotahi.
Marlborough Mayor Nadine Taylor said the estimated cost of the damage to the transport network from the 2021 and 2022 storms would run well into the hundreds of millions of dollars.
The Marlborough community was unlikely to accept large rates increases to repair rural roads that may be subject to further severe weather events, and applying for government funding via Waka Kotahi required a business case to be put together.
Taylor said consultants had looked closely at the Sounds economy and community wellbeing, sought to predict future travel demand and potentially expand marine-based transport options.
More than 500 people attended public meetings in February, and that feedback was being used to inform the potential future transport options.
Engineers have also assessed the Marlborough Sounds geography, geology and natural hazards including earthquake risk and sea level rise.
Taylor said Stantec had identified 29 options across the five geographic areas of the Sounds in response to the evidence gathered. The options align with the guidance provided by the government's climate change National Adaptation Plan.
The council expects to be in a position in mid-late June to propose an indicative preferred option for each of the areas; Rai Valley to French Pass, including Tennyson Inlet and D'Urville Island; Pelorus, including Kaiuma Bay Road; Kenepuru Road and the outer Sounds; Queen Charlotte Drive; and Port Underwood.
"Unfortunately for affected homeowners and businesses in the Sounds, there is still a long way to go before we'll have a fully-fledged, costed and funded plan. I know there is nothing worse than uncertainty and my heart goes out to residents and businesses who currently feel they are in limbo," Taylor said.
"The only plus in this whole process is that it gives everyone the chance to take a long, hard look at what a safe and resilient transport in the Sounds could look like in the long-term. My hope is that the government will come to the party and help us build a road and marine network that is far more resilient than the old one was."
She said recovery work was continuing as the business case was put together. The Marlborough Roads Recovery Team was working on a number of maintenance works to improve road resilience across the roading network, heading into winter.
Work was underway to replace 30 culverts throughout the network that were damaged as a result of the storm. Repairs to some road pavements for improved vehicle access was ongoing. On the unsealed roads, there was grading and gravelling work underway.
Complex repairs that did not prevent access were on hold, being considered part of the Marlborough Sounds Future Access Study.
The council recently made a request to Waka Kotahi for a further $52.4 million to complete repairs for areas mostly outside the study area, however it did include some work to hold and maintain current roading standards within the study area.