Global health experts are to warn that processed meats such as bacon, ham and sausages are as big a cancer threat as cigarettes, it has been reported.

The classifications, by the WHO's International Agency for Research on Cancer, are believed to regard processed meat as "carcinogenic to humans", the highest of five possible rankings, shared with alcohol, asbestos, arsenic and cigarettes.

World Health Organisation will publish a report on Monday on the dangers of eating processed meats.

As international health experts prepare to publish the report on potential cancer risks linked to red and processed meat, industry groups are bracing for a damaging blow to consumer confidence.

Global health experts are to warn that processed meats are as big a cancer threat as cigarettes.

The World Health Organisation's International Agency for Research on Cancer (IARC) gathered health experts in France this month to discuss available research on such meat, with a view to classifying them on its scale of cancer risks. The conclusions will be published on Monday.

The review has prompted lobbying efforts from meat industry representatives who fear a headline conclusion about a likely cancer risk could tarnish the image of certain types of meat, just as previous IARC recommendations did with diesel fumes and the common weedkiller glyphosate.

A report yesterday in British newspaper The Daily Mail saying the IARC would give processed meat the highest carcinogenic risk rating and red meat the second-highest one, drew immediate criticism, in particular the US livestock sector.

The IARC said it would not comment on media reports, but would publish the outcome of its review on Monday morning, at the same time as a report to be published in scientific journal The Lancet Oncology.

Shalene McNeill, executive director of human nutrition research at the National Cattlemen's Beef Association, said the available scientific evidence does not support a causal relationship between any type of red or processed meat and any type of cancer.

"Cancer is a complex disease that even the best and brightest minds don't fully understand," said McNeill.

Cancer is a complex disease that even the best and brightest minds don't fully understand

"Billions of dollars have been spent on studies all over the world and no single food has ever been proven to cause or cure cancer."

Producers say meat provides essential protein, vitamins and minerals as part of a balanced diet. Red meat includes beef, pork and lamb, but not poultry.

The IARC already recommends avoiding processed meat and limiting red meat intake, and health experts in Britain advise limiting processed meat consumption for bowel cancer prevention.

But while there was a statistical association between eating processed meat and bowel cancer, "the size of the effect is relatively small, and the mechanism is poorly defined", said Ian Johnson of Britain's Institute of Food Research.