Norwegian expedition cruise line Hurtigruten has finalised a deal to power some of its ships with dead-fish waste.

It has signed a seven and a half year contract with compatriot Biokraft to supply climate-neutral liquefied biogas (LBG).

The owner said this is the largest-ever global contract for LBG.

There will be near-daily delivery of biogas produced from organic waste to Hurtigruten vessels.

"This is a large and significant move for Hurtigruten, for Biokraft, for green solutions in the global shipping industry, and most importantly, for the environment," Hurtigruten CEO Daniel Skjeldam said.

The company is replacing conventional engines with gas-powered systems and large battery packs on at least six ships by 2021.

The hybrid vessels will run on a combination of clean electric power, LNG and LBG.