The Mental Health Minister, Helen Morton, says a new campaign by the Church of Scientology is sensationalist.
A group called The Citizens Committee on Human Rights, which is part of the Church of Scientology, has advertised in newspapers and distributed pamphlets warning people about changes to the WA Mental Health Act.
They say under draft changes to the Act, children could receive treatments such as sterilisation, psychosurgery and electric shock treatment without the consent of their parents.
But Ms Morton has told the ABC the Competent Minor Test is a safeguard which requires a doctor to determine first whether a child is capable of understanding the medical procedure in question.
"They can demonstrate that the young person is well informed, and that there are occasions when it is appropriate for a competent minor to give consent to medical treatment," she said.
"Rather than make these children or these young folk a ward of the state, as long as the doctor is satisfied that the person is well informed and fully understands what they are consenting to, then they can make that choice."
The Citizens Committee on Human Rights says the purpose of the campaign is to encourage people to read the proposed bill and approach raise any concerns they have with the Mental Health Commission.