An Australian man with swine flu died on Friday but the cause of death was uncertain, leaving it unclear whether he is the virus's first Asia-Pacific victim.
The 26-year-old, who had "a number of major medical conditions" passed away in an Adelaide hospital, officials said.
"Although the patient was diagnosed as positive for swine flu yesterday, his other medical conditions had dramatically deteriorated by the time he got to Adelaide," said South Australia's chief medical officer Paddy Phillips.
Australia has so far registered no swine flu deaths despite counting 2,330 cases of the A(H1N1) virus, making it the region's worst-hit country.
"It is with deep sadness and regret that we announce his death, and we offer our most sincere condolences to his family," Phillips said in a statement.
The man from West Australia was transferred from Alice Springs to the Royal Adelaide Hospital in critical condition on Monday and was diagnosed with swine flu on Thursday.
A health official told AFP that the unnamed man's cause of death was not expected to be established until at least Saturday.
"Tragic though this case is, it is important to note that in the great majority of cases, swine flu causes a mild illness which people recover from without any medical intervention," Phillips said.
Swine flu has spread rapidly in Australia, which is now entering the southern hemisphere winter, helping persuade the World Health Organisation (WHO) to declare the first global pandemic in 40 years.
The A(H1N1) virus has infected nearly 40,000 people around the world in 89 countries and territories, causing 167 deaths since late March, WHO figures show.