Nazi scientists worked on ways to use malaria-carrying mosquitoes as a weapon during World War II, a German researcher says.

At an entomological institute created at the concentration camp in Dachau, researchers were tasked with studying insects that can "inflict harm to humans," Klaus Reinhardt of Germany's University of Tuebingen said.

Historical documents from the institute's archives suggest "biological weapons [using mosquitoes] could have been developed as an offensive, not defensive, weapon," Reinhardt told TheLocal.de.

There is evidence Nazi researchers discussed the possibility of dropping insects from the air "on a large scale," he said.

By 1944 the institute had chosen a specific breed of mosquito most suited to a potential biological attack, but tests with mosquitoes infected with malaria were never carried out, Reinhardt said.

The entomological institute, created in January 1942 by SS head Heinrich Himmler, was headed by insect researcher Eduard May, who died in 1956.

"My opinion is that May knew that he did offensive warfare research," Reinhardt says.