Japanese beer brand Suntory's cans are on display as consumers shop for beer at a food store in downtown Tokyo. (EPA Images pic)

TOKYO: Japanese authorities raided four major beer manufacturers Wednesday over suspicions they colluded to hike beverage prices in a violation of anti-monopoly laws, a source familiar with the matter and the firms said.

Under investigation are Asahi Breweries, Kirin Brewery, Sapporo Breweries, and Suntory - four giants that reportedly make up around 90% of Japan's beer market share.

In a first, the Japan Fair Trade Commission (JFTC) conducted on-site inspections to probe "the allegations regarding a wholesale beer pricing cartel", the source, requesting anonymity, told AFP.