The father of a young man who died under mental health care has issued a heartfelt plea to the Government.

Dave Macpherson has asked for a meeting with Associate Health Minister Peter Dunne to discuss a ministerial inquiry into the mental health system.

His son Nicky Stevens died after disappearing from Hamilton's Henry Bennett Centre two months ago, and two more people have since died under mental health care.

Macpherson insists the Government isn't to blame for mental health problems, but it has a responsibility to treat them seriously.

"They have a responsibility along with the rest of the community to treat it more seriously than they do at the moment."

Prime minister John Key says the incidents are "isolated", but Macpherson says there is a systemic problems the Government needs to address.

"John Key has been very blase about the whole thing," he said. "It hurts us to hear something like that."

Key maintains security at mental health facilities is always a difficult balancing act.