Port Otago is detailing plans to spend $30m over the next two years.

It will deepen parts of the Otago Harbour channel, allowing larger container vessels and cruise ships to access Port Chalmers.

The company also plans to deepen the berths where large container vessels can sit.

That means new sheet piles will be installed, to reinforce the current wharf structure.

More warehousing will be built at Port Chalmers and Sawyers Bay, increasing storage capacity by more than a quarter.

The company also plans to buy a new tug and barge for about $7m.