Legal action has been taken by the Resident Doctors Association over Waikato District Health Board's hard-line staff vaccination policy.

The DHB's policy of requiring staff to get flu jabs or wear masks has resulted in three workers being suspended after refusing to comply.

Resident Doctor's Association National Sectary Dr Deborah Powell says the association wrote to the DBH asking them to meet and discuss the matter, but they never got a response.

"It's sad it comes to this, where you can't even stop and have a sensible discussion with the District Health Board. But if they're refusing to engage with us, which they are at the moment, then legal action is the only thing that's left open to us."

The Resident Doctors Association has taken the case to the Employment Relations Authority.

Dr Bill Hodge of Auckland University says health and safety policy is often "trump card" in the medical industry and the legal action is unlikely to succeed.