Mallette is concerned about 19-year-old Bieber's health and behavioural issues after it was alleged that he does drugs, Contactmusic reported.
"I think so many people go into the entertainment industry with amazing Christian roots and they go in with the right morals and they get influenced somehow," she said.
"I ask that people keep me and Justin in their minds. I pray for him every day," she added.
Mallette, who was 17 when she gave birth to Bieber and had
herself faced drug issues in the past, said that her son's partying habits should not be blamed for his behaviour.