The animals, which first tested positive earlier this month, were from Miyagi prefecture in northeast Japan and will mark Japan's 18th and 19th cases of BSE, if final tests are confirmed in a few days' time.
According to reports in the Japanese press, tissue samples of the animals - a ten year old Holstein and an eighteen year old Japanese Black - have been sent to the National Institute of Infectious Disease in Tokyo for further screening.
In February earlier this year, Japanese health officials diagnosed the first human to have contracted variant Creutzfeld Jacob's Disease (CJD) - the human form of the fatal, brain wasting disease. Beef from infected cattle entering the food chain is believed to have caused the fatal human condition, variant CJD.
The Japanese Food Safety Commission has since said, however, that the country's BSE testing regulations could be relaxed, after concluding that not testing cattle under twenty months of age would pose no risk to human health (previously Japan's policy was to test all animals).
Meanwhile, the US Department of Agriculture confirmed that it is to send a team of experts to South Korea and Japan in an attempt to resume exports of US beef and beef products.
South Korea and Japan halted US beef imports in December 2003, after a sole case of BSE was found in a cow imported to the United States from Canada.
Japan, which also is the US' biggest export market for beef products, has declined to issue a date on which to restart imports - something which has attracted criticism from US producers, many of which claim the decision to ban US beef is a thinly veiled attempt to protect its own domestic beef industry.
Japan has repeatedly rebuffed these accusations, however, claiming that its decision centres on food safety concerns and not trade disputes.
"We look forward to these opportunities in South Korea and Japan to further demonstrate the safety of US beef and that our system complies with international science-based guidelines for trade," said US Agriculture Secretary Mike Johanns in a statement earlier this week.