Staff at a major mental health hospital say they have been gagged from speaking out about abuse.

Reports say Latrobe Regional Hospital (LRH) chief executive Peter Craighead has warned mental health staff to stop speaking out about violent attacks against hospital staff.

It comes amid a spike in violent incidents at the Gippsland facility, with about reported 324 incidents of “occupational violence and aggression” in 2017-18.

Staff say they often do not report incidents, meaning that number should probably be higher.

Health and Community Services Union acting state secretary Paul Healey says the CEO told staff “there's no crisis in mental health … only a perceived crisis”.

“But we know from our members that there are serious problems with managing the services and staffing,” Mr Healey told the ABC.

“The hospital says; ‘If you speak to the media at all, you will be disciplined’ and we think that's unfair — people have the right and the freedom to speak,” Mr Healey said.

“What they're out to do is improve services, not make them worse.”

Mr Healey said if the claims that staff had been told to stop talking to unions too, it would constitute adverse action.