The Department of Conservation (DoC) expects to break ground on the country's next Great Walk before the new year despite delays.
It has been more than two years since the Tuatapere Hump Ridge Track was announced as the next Great Walk.
It was originally expected to open late next year with an upgrade budget of roughly $5 million.
DoC southern South Island operations director Aaron Fleming anticipated the final budget could be up to $7 million and the track would open a season later than planned.
COVID-19 was one of the causes of the delays, Fleming said.
"Those initial costs are always really indicative because it's not until you do the work to understand what the work is - the geotech, the engineering, you understand how much work might be required to the track," he said.
"It's not until you do the detailed work that you understand what the full cost might be."
Most of the work needed was on the track itself and to ensure it would be resilient to climate change as well as earthquakes.
"It's keeping the track safe and resilient for elements of climate change and things that might come our way in the future in terms of rain events and coastal erosion in particular," Fleming said.
DoC was assessing how long the three viaducts the track crossed could be used by walkers.
"It may mean in some kind of earthquake, some of those structures may be less accessible for walking across so we're looking at that now and doing the work around what does that mean for the Hump Ridge Track if that scenario came about," Fleming said.
Options on the table included swing bridges or bypasses which would impact the final cost, he said.
Fleming expected ground would be broken before the end of the year.
"It's imminent so we're not far away from seeing a spade in the ground and we're looking forward to that day."
Trampers could continue to use the track during the upgrades, but Fleming asked for people to be mindful of the work.
"Since the track was announced to be the next Great Walk, it's become a lot more popular and a lot more people are gravitating themselves to the track which is great.
"But we are working towards 2023-24, we have had a few delays along the way - COVID being one of them."
The upgrades were also designed to make the loop track a bit easier.
"It is one of the longer Great Walks. It sits around 60-odd kilometres across the three days and two nights," Fleming said.
It would be made easier by lifting the track standard, removing some of the muddy areas by putting in boardwalks, and building staircases to reduce the steepness for some parts of the track, he said.
About $200,000 had been spent so far with engineering and geotechnical work undertaken to understand the risks in the environment they were working in.
DoC was working through the detailed planning and had yet to go through the tendering process.
"We've got the high-level concept that we're working towards and we're working on some of the more detailed plans at the moment in terms of the track."
DoC had been speaking with mana whenua, the community, and local council to ensure the track met their expectations, he said.
Storytelling and interpretation boards would be one of the focuses beyond upgrading the track surface and working out carparking.
"We really want this to be an exciting journey for people when they're walking the tracks so ensuring that the information or the storytelling that we can share along the way is going to make people really connect with their surroundings," Fleming said.
"With this walk, we have the amazing opportunity of having heritage stories, the mana whenua and the history and this amazing site with the previous forestry, plus the wonderful biodiversity, the views and the landscape."