The government has ordered an investigation after a boy who took Tamiflu made by Swiss firm Roche, jumped to his death from the building he lived in, officials said.

The 14-year-old boy was pronounced dead Tuesday after leaping from the 11th floor of a condominium in the northern Japanese city of Sendai, police said.

'According to our information, the boy woke up in the middle of night after taking the medicine,' a local police spokesman. A short time later the youth jumped off the building.

In another case allegedly linked to Tamiflu, a 14-year-old girl jumped to her death earlier this month from a condominium in central Aichi prefecture.

The health ministry said it would study Tamiflu, but stopped short of immediately linking the drug to the deaths.

'The connection has not been made clear, but if that's the case then we will have to study special measures,' Health Minister Hakuo Yanagisawa told reporters.

The ministry ordered Japan's Chugai Pharmaceutical Co., which imports the drug, to provide information to assist a government investigation into the latest deaths, a health official said.

As of November last year, 54 people have died after taking Tamiflu, 16 of whom were 16 years old or younger, the health ministry said without drawing a direct link.

The cases led to a probe by the US Food and Drug Administration, which concluded last year that there was no evidence linking Tamiflu and the deaths in Japan.

Tamiflu is considered a frontline drug against a potential pandemic of bird flu or other forms of influenza. Japan buys more than 60 pct of the world's Tamiflu as a protective stockpile.