Doctors and researchers taking money or lunches from drug or device sponsors has been called out as "unacceptable" by the editor of leading medical journal.
The journal, BMJ, has launched a global campaign to separate medicine from big Pharma.
Academics have called for Government's to start funding independent trials of new drugs and medical devices, as well as for medical associates to discourage doctors from going along to industry-sponsored education events.
BMJ editor in chief Dr Fiona Godlee told TVNZ1's Breakfast this morning that pharmaceutical and device industry influence changes the research by favouring the product a sponsor is trying to market.
"What we've got is a situation where researchers and doctors are taking money or being funded in more indirect ways and I think it's really unacceptable."
Dr Godlee said it can often look innocent - a doctor supporting an educational event - but that there was strong evidence to show even taking a small amount of money or getting a free lunch does change a doctors prescribing behaviour.
"It's kind of what we call a dose response curve - so the more you get, the more that changes your behaviour. So more lunches, or more kind of favours of that sort, tend to increase the amount of inappropriate prescribing that doctors do."
She described big Pharma as a "complex cultural concept". It consists of early development of drugs, to marketing evaluation and lobbying.
"Pharmaceutical and device companies do some really good work and they have a very legitimate role at the beginning of the process - developing, innovating - but the point I think we're trying to make is they have no really legitimate role in evaluating whether those treatments or those devices are good or bad - what are the benefits, what are the harms. That has to be done independently."
In some places overseas, some pharmaceutical and device companies put money into a central pot that is then allocated for independent evaluation which Ms Godlee said had been working well.
But she added most of the drug trials that are used to approve new drugs are funded and done by industry.
"Industry tends to mange the trials, they tend to hold onto the data - it means people can't see data and look at it independently so there's quite a lot of hidden activity behind the scenes.
"The regulatory situation could be much more independently driven and we could have a situation where trialists shouldn't be taking money from industry if they're going to have public funding to do their trials."