Japan's agricultural ministry has said it will not lift a business suspension on Nippon Meat Packers, the company responsible for a beef-labelling scandal, until it finishes the inspection of all the beef in storage.

The Ministry of Agriculture, Forestry and Fisheries said the additional probe is necessary to respond to the fierce public criticism and doubts about the safety of the company's products.

The government will not lift a suspension on Nippon Food until it finishes inspecting all its beef, totalling more than 100 tons, for which Nippon Food had requested subsidies.

Nippon Meat Packers said founder and chairman Yoshinori Okoso, vice chairman Shigeo Suzuki and one other executive will step down tomorrow.

The meat processor said at last week's press conference the chairman would become an honorary chairman, and Suzuki would become supreme adviser. But the move faces growing criticism from consumers and the agriculture minister.

The ministry made public the results of its inspection between 21-25 August of Nippon Food's offices and warehouses in western Japan. The government officials confirmed evidence of disguising 3.1 tons of imported beef as domestic beef.

Nippon Meat Packers had admitted the unit sold 3.6 tons of the disguised beef to an industry body to receive subsidies under a government-run beef buyback plan aimed at helping businesses which were affected by the mad cow disease outbreak in Japan last year.

Though all the 3.6 tons of beef at Nippon Food's warehouse in western Japan were suspected of being imported beef, the inspection by the ministry officials could not determine the origin of 410 kilograms of beef that Nippon Food admitted it mislabelled.

But the ministry said some of the beef Nippon Food's other offices asked the government to buy back, contained a small amount of imported beef as well as domestic beef which wasn't eligible for subsidies.

Nippon Food's office in central Japan told the ministry 292 kilograms of beef for which the office requested subsidies may have included 15 kilograms of imported beef.

The ministry inspection confirmed those 15 kilograms were imported. It also found another nine kilograms of imported beef which Nippon Meat Packers' internal probe failed to discover.

Another office in western Japan submitted to the industry body 148 kilograms of Japanese beef which was not eligible for subsidies. The company told the ministry the submission occurred by mistake.

Other Nippon Food offices mismeasured the amount of domestic beef, but there was no evidence of mislabelling, the ministry said.