Upgrades to the main wharf of Port Nelson will allow visits by larger container and cruise vessels, and will increase the port's resilience in a major earthquake, according to the chairman.
The company has announced a $30 million wharf upgrade, and investment in a new tug to handle larger ships.
Port chair Phil Lough said 100 metres of the existing wharf, most of which is close to a 100 years-old, is to be re-built which will make it a full heavy-duty berth of 280 metres in length.
Port Nelson is owned by the Nelson and Tasman councils, which said the size of container vessels servicing the port has risen significantly in recent years, and the trend is likely to continue.
The upgrade will also mean the wharf will be capable of standing up to a major earthquake, allowing shipment of emergency supplies and fuel to continue, Mr Lough said.
"It's a big job replacing a wharf and making it as earthquake-proof as we possibly can.
"That is also a standby thing for emergencies supplies into Nelson in the event of a catastrophic earthquake."
Mr Lough said the search is on for a more powerful tug to assist larger ships, including cruise ships transiting the narrow harbour entrance.
"We're in the process of looking for another tug for the significantly higher level of grunt (needed). We've got people in the market at the moment, looking at potential tugs that could fit the bill."
Mr Lough said the increased towage power of a new tug should also assist the port to secure additional visits of larger cruise vessels that have not called into the region up until now.
"This increased tug capacity of 70 tonnes bollard pull will give us the necessary power to berth larger ships than we can currently handle, as well as give us the ability to extend berthing and sailing windows for vessels currently using the port."
The purchase will follow that of the tug Toia which arrived in Nelson in September 2016.
Planning work for the wharf development is likely to begin early next year with contractors likely to be on site around July 2019 to start the groundworks, Mr Lough said.
He said the project is due to be finished by mid 2020.