A US plan to develop a bad breath bomb and a chemical weapon to make enemy soldiers sexually irresistible to each other has been revealed in newly declassified documents.

New Scientist's web site reports that the documents show the Pentagon considered a range of non-lethal chemical weapons aimed at disrupting enemy discipline and morale.

The "sex bomb" idea would cause a "distasteful but completely non-lethal" blow to morale, it states.

Also considered were concoctions that would be irresistible to wasps or angry rats to render enemy bases uninhabitable.

And there was the bad breath bomb idea - a weapon that caused "severe and lasting halitosis" to make it easier to sniff out spies.

Other ideas dating back to 1994 from the US Air Force Wright Laboratory in Ohio included making soldiers' skin react painfully to sunlight.

--smh.com.au