Norwegian cruise and ferry group Hurtigruten is heading to domestic shipbuilder Kleven for up to four new polar expedition ships.

The vessels, which consist of two firm units and two options, represent its biggest ever investment.

Hurtigruten said the first 600-passenger, 140-metre ship is due in June 2018 and the second a year later. No price has been revealed.

“It is a milestone for us, Norwegian tourism and Norwegian shipbuilding.