Despite having previously starred in an advertising campaign for a range of sun creams, Bundchen said she does not use the products herself.
"I cannot put this poison on my skin," she said, referring to the widespread use of chemicals in lotions to absorb UVA and UVB light.
Dr Dolival Lobao, head of dermatology at Brazil's National Cancer Institute, condemned her comments.
"Sunscreen prevents damage to the skin and is of fundamental importance for the prevention of cancer," the Telegraph quoted Lobao as saying.
"This is not any poison. When a public person makes a statement like this, it creates confusion and I find that regrettable," Lobao added.
Jessica Harris, senior health information officer at Cancer Research UK, said: "Using sunscreen with at least SPF15 can help to protect your skin, along with spending some time in the shade and covering up with clothing.
"Sunscreens are fully tested before they can be sold and are not harmful to the skin," Harris added. (ANI)