A pollock-based egg substitute made by Japanese seafood giant Nissui is getting a surprise sales boost as the Asian country's egg supply is being impacted by the most severe outbreak of bird flu in its history.

Originally aimed at consumers with egg allergies, sales of the product have rocketed over the past six months as egg buyers scramble for alternatives, according to Japanese news agency, JiJi Press.

The product is aimed in particular as a replacement for tamagoyaki, an egg-based omelet that is a Japanese staple used as a breakfast food or as a side dish in bento boxes.