A $3 billion privately funded development in Otago is set to create New Zealand’s largest inland port, in a move expected to future-proof South Island freight logistics and significantly boost export capacity for the region’s primary industries.
The Milburn Quadrant development, located north of Milton, will span more than 200 hectares, including a 55-hectare inland port directly connected to State Highway 1 and the South Island’s main trunk rail line. Already zoned for heavy industrial use, the site will require no public infrastructure investment.
It comes as Dunedin’s Port Otago, currently the country’s sixth-largest seaport by export volumes, is facing capacity constraints.
The new development aims to provide an alternative to ease pressure on the port and support sectors such as forestry, dairy and aquaculture.
Mark Johnston, land and delivery manager at Calder Stewart, the developer behind Milburn Quadrant, says the facility would act as a “pressure relief valve” to alleviate storage constraints at Port Chalmers.
“Milburn is a shovel-ready, future-facing development that solves real capacity issues for our exporters. It’s fully privately funded, so it won’t burden ratepayers and offers the scale and connectivity our regional economy urgently needs,” Johnston says.
He says freight volumes from Central and South Otago were forecast to grow 30–40% over the next decade, largely driven by seasonal peaks in forestry and dairy exports.
“With Port Chalmers facing container storage limits and the cost of upgrading alternate sites like Mosgiel projected at over $100 million in public spending, Milburn offers a scalable, investment-ready solution designed to meet the growing needs of the Otago-Southland region, without placing an immediate burden on ratepayers or requiring upfront public funding,” he says.
“This region is heading into a logistics bottleneck. Without scalable inland port infrastructure, exporters will face rising costs, road congestion and lost opportunities. We estimate Milburn could eliminate over 10,000 heavy truck movements per year by shifting volume to rail.”
Johnston says the development would also better accommodate bulky, seasonal forestry exports that require storage and staging space not suited to smaller hubs.
Calder Stewart has already completed Stage 1 of the project, which includes a 10,000 square metre steel fabrication facility and offices at Revolution Hills. The company plans to build out the port infrastructure using its in-house property, design, construction and manufacturing teams.
“In addition to being New Zealand’s largest industrial landowner, we’re also a vertically integrated property development and construction business with decades of experience in building large-scale infrastructure,” Johnston says.
“With concrete, steel, cranes and a local labour force already on-site, we can deliver faster and more efficiently than anyone else in the market.”
Construction on the inland port is expected to begin within 24 months, subject to resource consent approvals. The port could eventually handle between 400,000 and 600,000 twenty-foot equivalent units (TEUs) per year.
In a first for New Zealand, all new buildings in the Milburn Quadrant will include rooftop solar systems, funded and installed by Calder Stewart Energy Limited. A 350kW system is already operational at the fabrication facility, and the development could ultimately generate up to 50MW of solar power.
“Occupiers will benefit from hedged solar pricing and building owners will share in the returns. It’s a self-funded energy model that’s already been submitted for national innovation awards,” Johnston says.
The site will also include 30-metre native planting buffers, walking trails, bridges, and a cycleway integrated with the Clutha Gold Trail.
“Milburn Quadrant will support hundreds of jobs, unlock industrial growth, and give exporters a long-term solution they can trust.”
Calder Stewart’s lower South Island business development manager of property, John D’Arcy, says the company was seeking local government support to fast-track approvals and would present the proposal to government officials and stakeholders in the coming weeks.
“Port Chalmers is approaching logistical constraints, particularly around container storage and log volume
“This is about real economic transformation, securing long-term freight capacity, creating hundreds of jobs, and easing the pressure on urban roads and infrastructure,” D’Arcy says.
“Milton is strategically positioned closer to the region’s agricultural producers, where the bulk of freight originates. That’s where rail delivers the greatest benefit, with both carbon and cost efficiency improving over distance. It’s a smarter, more sustainable hub for Southland and Central Otago producers.
“What we need right now is visibility, political backing and certainty around regulatory timelines. With the right support, we can secure council approvals and ensure the public understands the scale and value of what’s being built here,” he says,
