Swiss company Roche, which markets the drug that stands in the front line of defence against a bird flu pandemic, appeared at an FDA committee hearing over possible risks attached to Tamiflu when taken by children.
"Based on the information available to us, we cannot conclude that there is a causal relationship between Tamiflu and the reported paediatric deaths," an FDA document submitted to the paediatric safety committee said.
Reports in Japan have said Tamiflu may have been a factor in several suicides by children aged under 16 who took Tamiflu to treat influenza.
The FDA has detailed 75 cases of mental and skin disorders worldwide, including 69 in Japan. The European Union's drugs agency has also asked Roche for a safety review into the drug.
The document posted on the FDA website attributed increased reports of psychiatric disorders among Japanese children who have taken Tamiflu to a variety of probable causes.
It said reviews of available information point to "an increased awareness of influenza-associated encephalopathy, increased access to Tamiflu in that population and a coincident period of intensive monitoring (of) adverse events".
An FDA spokeswoman declined to comment on the panel's findings as the hearing was still ongoing. Tamiflu was one of eight drugs being reviewed by the committee 12 months after they were approved for use by children.
Roche insisted to the FDA hearing that Tamiflu is safe, saying it has had no indication that the drug could lead to the kind of side effects documented in Japan, such as hallucinations, delirium and convulsions.
"Based on the information available to us, we cannot conclude that there is a causal relationship between Tamiflu and the reported paediatric deaths"
US Food and Drug Administration document
"Roche doesn't believe there's a link between Tamiflu and those deaths, and we are confident that Tamiflu can be used safely both by children and adults," a spokesman for Roche in the United States, Al Wasiewski, said on Thursday.
Countries have placed huge orders for Tamiflu to guard against a feared pandemic of flu that could derive from the H5N1 avian influenza virus.
The strain has killed more than 60 people in Southeast Asia since 2003 and since last month has been found in Europe, Canada and the Middle East.
Roche said that more than 30 million people worldwide - including 11.6 million under-16s in Japan and the United States - have taken the influenza treatment safely since 2001.
In a report submitted to the FDA committee, Roche stressed that there was "no causal relationship" between Tamiflu and any of the reported deaths in Japan or mental health problems.
"There is no increase in adverse events for children on Tamiflu versus children with influenza in general," the document said.