Venezuelans are expressing dismay over the death of an eight-year-old boy with non-Hodgkin's lymphoma who had become a symbol of the crisis-wracked country's collapsed healthcare system.

Oliver Sanchez gained fame in February when he appeared with his mother at a demonstration to protest medicine shortages wearing a mask and holding up a homemade sign reading, "I want a cure, peace and health."

Sanchez died on Tuesday, sparking outrage on social media and in congress. Opposition MPs in the National Assembly held up pictures of the second-grader to denounce what they called an avoidable death. A popular cartoonist dedicated a drawing to him dressed as an angel with a white dove in his hands.

The boy's mother, Mitzaida Berroteran, told local newspaper El Nacional that in the absence of readily available and affordable drugs she had to scour social media for donations.

"Each time they prescribed us something we had to run," said Berroteran, who thinks her son contracted a deadly bacteria while interned in a public hospital in western Caracas.

Low oil prices and a deep recession are causing widespread shortages in Venezuela, with everything from prescription medicines to basic foodstuffs going scarce.