Nestle is to open its first factory in Japan for 26 years due to demand for exotic flavours of Kit Kat such as wasabi, green tea and sake.

The new plant will begin production next month in the country's western city of Himeji, and will specialise in making upmarket versions of the chocolate wafer snack popular with both locals and tourists.

Japan sell more than 30 flavours of Kit Kat that are considered gourmet treats and sell as box sets in upscale stores for as much as 3500 yen (£24, $31), more than ten times the price of a standard bar.

These chocolate flavours – which include purple yam and grapefruit – are a popular novelty with tourists from other parts of Asia such as China and South Korea, as well as Europe.

Spending by visitors on confectionery has more than tripled in the four years to 2016 to £900bn, according to Japanese government figures.

"We take pride in our unique flavours and I think that makes Japan special in the Kit Kat world," a Nestle spokesman told Bloomberg News.

Another thing in the bar's favour is that Kit Kat in Japan sounds close to the local phrase "kitto katsu," or "sure win".

That has helped turn the product into a popular gift for people about to take exams, or begin important projects. The bar is a particularly popular gift during school entrance exam season.

However, Switzerland-based Nestle has no plans to export Japan's rarefied Kit Kats.

A Nestle UK spokeswoman told IBTimesUK: "These types of flavours are particular to the Asian and the Japanese market. We have no plans to sell them in Britain."