A woman who nearly suffocated her newborn son after falling asleep on him later breastfed him in hospital while she was high on meth. 

"Parenting is the most important job any human being has," Judge Jonathan Krebs told the woman as he sentenced her to five months community detention. 

"You failed this baby significantly. And you know that. 

"Whether the baby will grow to manifest any long-term consequences will remain to be seen." 

The woman has previously come to the attention of authorities when she fled hospital with another child who wasn't allowed to be in her custody. 

She no longer has custody of any of her children. 

The most recent offending happened when her youngest child was just one month old. 

The court heard she had fallen asleep on top of the baby, nearly suffocating him. 

While at the hospital receiving treatment for him, the woman went to her car and injected methamphetamine before going back inside and breastfeeding her son. 

Meth was then found in the child's bloodstream when the hospital ran tests on him. 

Several years ago the woman was convicted of smuggling another baby out of hospital to avoid having to hand the child over to Child Youth and Family. 

Oranga Tamariki - then known as Child Youth and Family - had obtained a custody order to take the child into its care shortly after it was born. 

Police located the baby unharmed within the day. 

The woman's lawyer, Mark Alderdice, detailed a lifetime habit of her using methamphetamine to cope with her own childhood trauma. 

"Meth is a way of coping and to block stuff out. 

"She acknowledges that she needs to find another way of dealing with the adversities of life rather than resorting to meth." 

Alderdice said his client was trying to get clean and wanted to have a meaningful role in her children's lives at some point. 

Judge Krebs sentenced the woman to five months community detention and 18 months intensive supervision. 

"Meth has turned you into a person who makes these kinds of appalling decisions," he said. 

"Your young baby has had to suffer as a result of those."