A Danish “biotech” company in which Novak Djokovic holds a majority stake is working on a “frequency” treatment for 1Covid1-19 that an expert says bears similarities to the principles of homeopathy.

The world No 1 men’s tennis player was forced to leave Australia on Sunday after the country’s immigration minister cancelled his visa on the basis that his presence in Australia might risk “civil unrest” as he is a “talisman of anti-vaccination sentiment”.

On Wednesday it emerged Djokovic had acquired an 80% stake in QuantBioRes, the website of which says it designs treatments for viral diseases and resistant bacteria through “predicting the electromagnetic frequency” that can interfere with a virus’s activity.

“At QuantBioRes, we work in utilising unique and novel Resonant Recognition Model … a biophysical model based on findings that certain periodicities/frequencies within the distribution of energies of free electrons along the protein are critical for protein biological function and interaction with protein receptors and other targets,” the website says.

It carries a quote from the Serbian-American scientist Nikola Tesla: “If you wish to understand the universe, think of energy, frequency and vibration.”

Dr Darren Saunders, an Australian biomedical scientist, said the approach described on the QuantBioRes website was reminiscent of homeopathy, an alternative and unproven treatment that claims illness-causing substances can, in minute doses, treat people who are unwell.

Homeopaths claim that by diluting these substances in water or alcohol, the resulting mixture retains an “imprint” of “frequency” of the original substance that triggers a healing response in the body by causing an energetic shift.

Saunders said in his opinion it was “a stretch” for QuantBioRes to call itself a biotech company. “The ‘innovative technology’ they describe on their website does not reflect contemporary understanding of how biochemistry works,” Saunders said. “If any athletes or other potential investors would like advice on not blowing their cash on this stuff, my fees are reasonable.”

The website says the company will “soon start testing different treatment approaches”, but a link encouraging people to “learn more” appeared to be broken when the Guardian attempted to access it. A link to a July 2020 announcement that QuantBioRes would test 1Covid1-19 deactivation mechanisms also appeared to be broken.

Prof Peter Collignon, an infectious diseases physician and antimicrobial resistance expert, said the QuantBioRes website used “fancy terms” without providing any evidence of success of the methods it promoted. “They’ve given nothing in the way of data,” he said. “People are looking out for new molecules all the time, but the website describes a way of finding a new molecule without providing any evidence of success.”

The chief executive of QuantBioRes, Ivan Loncarevic, denied that the methods developed by his company had anything to do with homeopathy, and defended the lack of data on the company’s website.

“What we do has absolutely nothing to do with homeopathy,” he said in an interview. “The theory behind homeopathy is that you can transfer information from a chemical to another substance, such as water. What we do is to develop peptides with specific functionality. This is pure, classical science.

“Of course we are not putting our data on our website for every idiot to look at. We will soon publish an article in a scientific journal that will collect all our clinical testing.”

When asked when the article would be published, Loncarevic said: “With a little luck, in two to three months, after peer review.”

Asked about Saunders’ opinion that it was “a stretch” for QuantBioRes to call itself a biotech company and that the “innovative technology” described on its site did not reflect contemporary understanding of how biochemistry worked, Loncarevic replied: “That’s because we are innovative.”

He said other pioneers in engineering or science, such as Elon Musk and Galileo, had faced similar criticism when first airing their views. On the subject of broken links, he said this was the first time he had heard of the problem and “it’s not [done] on purpose”.