SYDNEY (AFP) - Australia will lose billions of dollars in tourism revenue as international visitors cancel trips in droves due to bush fires raging across the country, an industry body forecast Friday (Jan 17).

The number of travellers booking visits to Australia has fallen 10-20 per cent since the fires began in September and the slump will cost the economy an estimated A$4.5 billion (S$4 billion) this year, the Australian Tourism Export Council (Atec) said.

"International visitors are cancelling because of fears around air quality, safety and the impact fires have had on our tourism offering as well as a lack of certainty on how long it will take for us to recover," Atec managing director Peter Shelley said.