The Ministry of Health, Labour and Welfare and the City of Osaka jointly inspected the factory in Osaka that had made the supplements containing "Beni-Koji" red yeast, suspected of having caused health damage, the ministry official said.

News footage showed officials entering the factory on Saturday, and the official said the ministry could search other related locations.

Yuko Tomiyama, head of Kobayashi's investor relations, told public broadcaster NHK the firm intends to sincerely deal with the matter and fully co-operate with the investigation.

Kobayashi said on Friday it was investigating a suspected link between the products and their effects on the kidney since it received reports of kidney disease linked to the products.

As of Thursday evening, 114 people had been hospitalised and five had died after taking the supplements, which were marketed as helping lower cholesterol levels, according to the company.

Kobayashi said it is examining the earnings impact of the latest issues.

Japanese Chief Cabinet Secretary Yoshimasa Hayashi criticised the company on Tuesday for its slow response, saying it was regrettable that Kobayashi took two months to announce the health impacts of its products.

The company has been recalling products with Beni-Koji in recent days after receiving reports of kidney ailments.

A Chinese consumers association urged consumers to stop using affected products, saying it was concerned about the risk of Kobayashi products, state media reported on Friday.

Beni-Koji contains Monascus purpureus, a red mould that is also used as a red colouring in some foods.

Puberulic acid - a potent antibacterial and antimalarial agent that can be produced from blue mould and can be toxic - was confirmed in a batch of the products that caused health complaints, Japanese media said.

Australian Associated Press