MANILA, April 27, 2009 (AFP) - Philippine health authorities on Monday urged people to avoid hugging and kissing at public gatherings due to worries about a possible global pandemic of the deadly swine flu virus.

There have been no cases reported in the Philippines but since the virus has killed at least 20 people in Mexico and possibly dozens more, authorities worldwide have stepped up health and safety measures.

The head of the Philippine health department's national epidemiology centre, Eric Tayag, said it was increasing monitoring of arrivals at airports and urged people to limit physical contact in public.

"Avoid touching, kissing and hugging," Tayag said.

The disease cannot be transmitted by eating properly cooked pork, but as a precaution the Philippines said at the weekend that pork products from the United States and Mexico were temporarily banned.

Philippine hog farmers have also been ordered to vaccinate their herds.

World Health Organisation (WHO) officials have warned that the new swine flu strain, apparently born after human and avian flu viruses infected pigs and became mixed, could further mutate.

The WHO recommended that all nations "intensify surveillance for unusual outbreaks of influenza-like illness and severe pneumonia."