KUALA LUMPUR - HAZE from forest fires that was shrouding parts of Malaysia will worsen the H1N1 flu situation by causing more respiratory illnesses, a minister said according to reports on Thursday.

Malaysia has announced 13 H1N1 flu-related deaths and some 1,426 infections, with the latest casualty a six-year-old boy who succumbed to pneumonia on Wednesday.

'I agree that the haze recurrence will complicate H1N1 cases,' Health Minister Liow Tiong Lai said according to the state news agency Bernama.

Mr Liow said the haze, which on Wednesday reached 'unhealthy' levels in six locations in Malaysia, would make people more vulnerable to infections.

'The H1N1 virus attacks the lung cells directly. It then causes serious pneumonia. Those with respiratory ailments have weaker immune systems and the attack can be more serious,' he said according to The Star daily.

Environment authorities have said that the haze is being caused by hundreds of forest fires blazing in the Indonesian provinces of Kalimantan and Sumatra, and in Malaysia's Sarawak state on Borneo island.

The Air Pollutant Index (API) recorded unhealthy levels in six areas on Wednesday morning, including a district of the capital Kuala Lumpur, two in surrounding Selangor state, and three in Sarawak.

The annual haze crisis hit its worst level in 1997-1998, costing the South-east Asian region an estimated US$9 billion (S$12.8 billion) by disrupting air travel and other business activities