Egypt's military leaders have been ridiculed after the chief army engineer unveiled what he described as a "miraculous" set of devices that he claimed detected and cured Aids, hepatitis and other viruses.

The claim, dismissed by experts and called "shocking to scientists" by the president's science adviser, is a blow to the army's carefully managed image as the saviour of the nation.

It also comes as military chief Field Marshal Abdel-Fattah el Sissi, who toppled Mohammed Morsi in July after the Islamist leader ignored mass protests calling for him to step down, is expected to announce he will run for president.

The televised presentation has raised concerns Egypt will be drawn back into the broken promises of authoritarian rule, when Hosni Mubarak frequently announced initiatives that failed to meet expectations.

Major General Taher Abdullah said two of the devices used electromagnetism to detect Aids, hepatitis and other viruses without taking blood samples while the third acted as a dialysis unit to purify the blood.