The man, from south London, had serious underlying health problems and was in Lewisham Hospital. Tests undertaken after his death showed he had the flu.

He is the fourth person with swine flu to die in the UK. Dr Simon Tanner, from NHS London, said London has seen a “spike” in flu cases in the past week.

London is the second-worst affected area, with more than 1,900 cases.

The fatality is the second in the Asia-Pacific region related to swine flu, following the death of a man in Australia on Friday.

Philippine Health Secretary Francisco Duque III said the woman’s chronic heart disease was aggravated by severe pneumonia. She started to have flu-like symptoms such as dry cough, fever, chills and difficulty breathing two days before her death on June 19.

A throat swab revealed she was also infected with the swine flu virus.

Duque said post-autopsy findings disclose that the death was caused by heart failure “aggravated by severe pneumonia either bacterial, viral or both.”

Given the available information, health authorities cannot conclude that the death is due to H1N1. In other countries that have reported swine flu deaths, the majority have had pre-existing conditions, he added.

Duque said the Philippines has 17 more confirmed swine flu cases, bringing the total to 445 — though 84 percent of the total cases have already recovered.

Australian authorities on Sunday listed a 26-year-old Aboriginal man who died in the southern city of Adelaide on Friday as a “suspected” swine flu death. Although the man had tested positive for the virus, authorities doubt it killed him because he also had pre-existing chronic diseases.

Meanwhile, the first case of swine flu was reported in Iran. A report on the Web site of the Iranian Health Ministry said the patient is a 16-year-old Iranian boy who lives in the United States and arrived in Iran with his parents.

The report did not identify the boy. It said the case was detected when he arrived at an airport in Iran with some symptoms of lung infection. The report says the boy was quarantined and he and his parents received medical care.