The 192 members of the World Health Organisation yesterday approved international rules giving the WHO sweeping powers to tackle disease outbreaks and other health threats.

The WHO said the need for new international health regulations had been underlined by the 2003 outbreak of severe acute respiratory syndrome (Sars) and the more recent bird flu epidemic in Asia. The current regulations, introduced half a century ago before the days of mass air travel and global mobility, cover only cholera, plague and yellow fever.

Under the new rules, countries will be required to report to the WHO any disease outbreak that could constitute "a public health emergency of international concern", to allow in WHO investigators and to show they are taking steps to control the outbreak.

The WHO will be able to issue its own recommendations, which could include travel restrictions, airport checks and quarantine measures that countries would be expected to follow.

"This is a major step forward for international health," Lee Jong-wook, WHO director-general, said yesterday.

The new regulations, which will come into force in two years' time, also confirm the WHO's right to use information gleaned from unofficial sources, such as the mobile phone messages and e-mails that spread news of the Sars outbreak in China.

Dr Lee said countries would now be under a legal obligation as well as international pressure to provide accurate information and allow in WHO inspectors in the event of a potential health emergency.

Max Hardiman, WHO co-ordinator for the regulations, said the Sars experience had taught governments that it was better to come clean than try to cover up. "It is now quite difficult to hide major public health events away. If governments don't tell WHO, it will get out anyway," he said.