Newly compiled data shows the companies sponsored hundreds of training sessions at the hospital between 2011 and 2015 at a cost of more than $50,000.

In August 2015, Novartis Pharmaceuticals Australia provided dinner and drinks for a diabetes and endocrinology workshop hosted by the hospital at a total cost of $1131, while in July 2014, Novo Nordisk Pharmaceuticals contributed $800 towards a diabetes workshop.

More than 50 of the other training sessions related to the treatment of cancer and came at a cost of hundreds of dollars each.

The figures were pieced together from publicly available documents by a group of academics led by the University of Sydney’s Bias in Research project, revealing what they describe as a “pervasive commercial presence in everyday clinical practice”.

One of the study’s co-authors and Sydney University postdoctoral research associate, Quinn Grundy, said the sponsored events were “a key part of pharmaceutical companies’ marketing strategy”.

“It’s a way for them to raise awareness about the diseases their drugs treat, a way for them to promote new products or to encourage higher diagnoses or treatments in the area,” she said.

“The concern is that you’re getting the sponsor’s side of the story and not an independent source of information on what is the most cost-effective, best and safest treatment.”

A number of the sponsored events come with the caveat that the companies were “not responsible for inviting the attendees or organising the educational content”, but Dr Grundy said “even a sandwich” could influence doctors’ prescribing habits.

“We know from research that’s been done in the US that physicians who received drug company payments even of $12 or $18 were more likely to prescribe those brand name, high cost, heavily marketed medicines than those who did not,” she said.

“We know it influences practice and we want to strive for independent decision-making.”

Dr Grundy called for the practice of drug companies paying to cater events at public hospitals to be banned, describing it as “low-hanging fruit”.

“I think it would probably be prudent to ban catering from drug companies, but that's a tough sell because everyone likes free food,” she said.

“Drug companies will say they have a really important role in education, but I can’t think of any other education setting where you’re guaranteed a free lunch, free dinner, or drinks, so if it’s really about the education they should at least be able to get rid of the food and beverages, but we would suspect that has much more of a marketing function.”

A spokeswoman for Bendigo Health said the hospital had worked with clinical staff to actively reduce sponsorship and support by pharmaceutical companies in recent years, with all sponsorship declared under its gifts and benefits policy.

“Professional bodies have guidelines in place to assist their members in ensuring they are not unduly influenced into making decisions that are not in the best interests of patients,” she said.

A spokesman for Novo Nordisk said engagement between health care professionals and companies that developed medications was “important and legitimate”.

“As the developer of medications, we are the authority on how it works, its interactions with other compounds, its efficacy and other relevant information,” he said.

“Any meals or beverages supplied at Novo Nordisk sponsored medical education events are secondary to the educational content, appropriate based on the duration of the meeting, and not excessive.”

Novartis was contacted for comment.