The Mental Health Foundation says it is concerned Taser use on those with mental illnesses will grow after the decision to arm frontline officers.
But police say they're getting better at dealing with people with mental illness.
It's intimidating for anyone, but mental health organisations say it can be worst for more vulnerable members of society.
"The whole idea of someone who is going through a crisis having a uniformed, armed police officer coming toward them is pretty alarming," says the Mental Health Foundation's Judi Clements.
The foundation says it is concerned at the prospect of all frontline officers carrying Tasers, and those with mental health issues are most likely to be in the gun.
"We've certainly seen a disproportionate use of the Taser in situations where the person [who] is on the receiving end has a mental health problem," says Ms Clements.
In March the Independent Police Conduct Authority released a report highlighting what it said were serious issues around how police deal with people in custody, particularly those with mental health issues. A mental health team was set up to give officers training.
Police say training is already paying off.
"The training is around countering stigma and discrimination, and also giving officers advice on how to deal with people who are in mental distress," says Inspector Sue Douglas, mental health project manager.
In 2014 alone, police dealt with 147 mental health-related incidents a day, and that's increasing 8 percent year-on-year. While statistics show Tasers are twice as likely to be used at mental health emergencies, police say with further training that'll likely come down.