Testimony from Tuesday's opening witness revealed that children as young as 12 are using the drug, with some becoming "trapped" in predatory relationships with drug dealers and suppliers.

The assistant senior counsel Sally Dowling SC also flagged the commission would be hearing evidence in coming days about the effects on children of pre-natal exposure to methamphetamine - a topic the commission has not yet covered.

"In the Hunter New England area there is a number of programs for mothers and women with substance abuse disorders," Ms Dowling said.

The first witness to appear at East Maitland Court House was Anne-Marie Connelly, the manager of client services for Family and Community Services' [FACS] Cessnock Community Services, said that she had witnessed a "trend of younger and younger people experimenting [with the drug] and being around people representing risks" in the region.

She said that over the past decade she has worked in the Cessnock area the inter-generational risk of using methamphetamine and amphetamine-type substances was becoming more apparent.

"I have seen families where that risk is increasing," she said. "The exposure to parents using has desensitised young people to the negative consequences ... It appears there's a higher likelihood of a young person using ice because of that inter-generational effect."

She said the biggest issues associated with parents using the drug were that children could experience neglect, inadequate nutrition, and exposure to a lifestyle that could bring "high risk people" into contact with them, occasioning a higher risk of physical and sexual harm in the home.

Ms Connelly said that of the 143 children who entered care in the Hunter district between July 1, 2018, and May 31, 2019, 59 children had parents who were impacted by the drug 'ice'.

She later clarified that these were not official figures from FACS.

Children as young as 12 were using the drug in the Hunter area, she said, which made them vulnerable to other risks.

"Certainly we have cases where young people have been kept in captive-like situations by people who have started supplying them and exhibited predatory behaviors," she said.

"The worst case scenarios there have been young men and women who have been seriously psychically and sexually assaulted over a period of time.

"Over the past twelve months there has been at least three or four cases where there have been elements of what I just spoke about."

Ms Connelly said there was one case in the region of a 14-year-old using the app Tinder to find people who would supply her with the drug.

"In exchange she was having to perform sexual favors."

She said that in cases where teenagers had become entrapped in an ice addiction as well as an abusive relationship with a supplier it was very difficult to break down that "psychological attachment".

The fact that the cost of a point of ice had almost halved in the region over five years, she said, was only making it "more accessible" to children and families.

"It appears to have increased appearance in schools in the area. It's just a more cost-effective drug than other substances."

She said that intervention in teenage and parental drug use was most effective when there was a "wrap around of services" assisting the child and their family.

"And an understanding of the relationships and connections the families already have within the communities," she said.

David Lowe the are manager of Juvenile Justice for the Department of Justice NSW and Susan Walton, the Community Corrections District Manager for Maitland, will speak on Tuesday afternoon.