Torstein Hagen-controlled Viking Cruises has expanded its orderbook with a deal for up to six new ships in Italy.

The owner has returned to Fincantieri for two firm vessels and four options.

The new cruise ships will be based on previous units handed over by the giant yard group.

Delivery of the first two vessels in the series will be in 2030.

The price has not been revealed, but Fincantieri classed the order as “large”, meaning between €500m ($540m) and €1bn.

The optional ships would be completed in 2031 and 2032.

The two companies have cooperated since 2012, with Fincantieri handing over 22 vessels to Viking since then.

In a joint statement, the owner and shipbuilder said the ships would continue innovation around eco-friendly fuels and of sustainable zero- emission power generation systems.

The small ships will be about 54,300 gt, accommodating 998 passengers.

Pierroberto Folgiero, the shipbuilder’s chief executive, said: “This agreement not only strengthens our orderbook, but it ensures further depth of work in our shipyards over the long term, positioning us at the forefront of driving the industry towards energy transition.”

Viking has a 10-ship fleet of a similar size to the newbuildings, plus one in a joint venture with China Merchants.

There are already eight new ships on order at Fincantieri in Ancona, with deliveries up to 2029.