New Zealand's wealthiest man, Graeme Hart, has just finalised plans for another superyacht to add to his collection.

In August, Hart was in Norway to watch his 107 metre $78 million yacht, Ulysses, being launched.

The latest superyacht will be ten metres longer than the Ulysses, and will have a helicopter deck and hangar, room for five large boats as well as smaller boats for expeditions and will accommodate 66 people, according to Norwegian naval architects Marin Teknikk.

"There will be arranged space for and deployment procedures for five large boats that can be carried on for different excursions," Marin Teknikk said. "In addition, there will be a hangar for several smaller boats and equipment for water sports. The latest technology on diesel electric propulsion systems will be installed."

The yacht builder Kleven Verft, based in Ulsteinvik, Norway, also built the Ulysses for Hart, work that Hart noted was impressive.

"I am very pleased with the quality of the work that has been done by Kleven, and how our organisations have worked together to bring this exciting project to life. I am very much looking forward to seeing both vessels being finalised," Hart said.

The Ulysses, which is expected to arrive in June, is the second Ulysses, with Hart's previous 58 metre luxury motor yacht also sharing the name. It has since been sold and renamed.

The latest two additions to Hart's fleet, which also includes a 77 metre superyacht, Weta, are both larger in length than both of the Royal New Zealand Navy's frigates and just 21 metres short of the Navy's largest ship, the HMNZS Endeavour at 138 metres.

Ulysses' naval architect, Paul Endre Saetre, said from Norway that Hart was working with Marin Teknikk as they usually designed offshore vessels for the oil industry.

"It is not a normal yacht design. Mr Hart wanted more of a rough, offshore design, to withstand rough waters," Saetre said.

The latest commissioned vessel is scheduled for delivery in July 2016.