Health authorities on Monday urged people to avoid hugging and kissing in public over worries about a possible global pandemic of the deadly swine flu virus.

The virus has killed at least 20 people in Mexico and possibly dozens more, prompting authorities worldwide to step up health and safety measures.

Eric Tayag, the head of the Department of Health's National Epidemiology Center, 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.

Health Secretary Francisco Duque said there had been no cases of the new strain of swine flu detected in the Philippines.

He said there was no ban on arrivals from Mexico or other parts of North America but asked Filipinos to "reconsider their plans" to travel to Mexico.

Health officials said 11 thermal scanners operating at the country's international airports -- first set up during the 2003 Severe Acute Respiratory Syndrome (SARS) outbreak in Hong Kong -- would detect any fever among new arrivals and that four extra scanners had been ordered.

District health officials have also been asked to be vigilant for outbreaks of flu or "atypical pneumonia" that might be a sign of swine flu.

Duque said the Philippines was merely "tweaking and improving the systems" already in place for preventing the spread of SARS and bird flu.

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.

Hog farmers in the Philippines have 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."