The study published in the online journal BMJ Open questioned almost 800 NHS staff, with few saying they felt adequately prepared to respond appropriately, with maternity services most likely to be presented with trafficked individuals.
Over half said they lacked the confidence to make appropriate referrals, with referrals for men vexing the most staff (71%).
Campaigners say that men are often overlooked because they don't realise they have been trafficked into the UK.
"They are quite difficult to identify because they might not even identify that they are a victim themselves," said Amy Jasper, UK Community Network Co-ordinator at anti-trafficking charity, Stop the Traffik to Premier.
"A lot of people want to be able to support their families and send money home, back to the people who might need it, and they might not actually realise they are being exploited," added Jasper.
Most participants (over 95%) had no idea of the scale of human trafficking in the UK, and three out of four (76.5%) didn't realise that without appropriate safeguards, a call to the police could put patients in even more danger.
"In particular [staff] lack knowledge about how to ask about experiences of human trafficking, how and when to contact law enforcement agencies, and how to make referrals to local and national support agencies," write the researchers.
International law requires that the UK provides victims of human trafficking with whatever medical treatment they require, which includes psychological help, counselling, and further information on support services.
It is thought that around 2.5 million people are trafficked every year, with every country in the world either a source, transit point, or destination.
Three out of four of those surveyed said they would be interested in targeted training around people trafficking, particularly those working in mental health and emergency medicine services.
The researchers caution that their findings may not be applicable to the entire NHS, but suggest that additional training for NHS staff could improve the wellbeing and safety of such a vulnerable group of people.
Listen to Amy Jasper speaking to Premier's Des Busteed:
