The sentencing of a 16-year-old Invercargill girl for dealing the class A hallucinogenic drug LSD to teens reflects an increase in the amount of hard drugs in circulation, police say.

The police summary of facts outlining the girl's case says drug dealing has become a widespread problem throughout Southland.

"Police have noticed a recent increase in the amount of serious drugs such as LSD, ecstasy and methamphetamine in general circulation," the summary says.

Principal Youth Court Judge Andrew Becroft last week sentenced the girl to six months' supervision with activities when she appeared in the Invercargill Youth Court.

The charges which she admitted - 16 counts of offering to supply LSD - carried a maximum sentence of life imprisonment, with the judge saying the girl only avoided jail because of her special circumstances which included a "tragic and difficult background".

He suppressed parts of her background.

The police summary says in December 2011 and January this year police began targeting active drug dealers, including the girl, within the Invercargill area.

Police intercepted text messages which revealed she was actively dealing in Class A controlled drugs, the summary says.

Between January 25 and 30 she sent and received about 16 text messages related to dealing LSD.

"These text messages clearly identified that she had LSD, ecstasy and amphetamines in her possession for the purpose of sale," the summary says.

When spoken to by police she admitted trying to sell LSD on behalf of her friends.

Judge Becroft said LSD was a highly addictive drug which could have devastating if not catastrophic consequences.

"To know LSD is in teenage hands is a disturbing fact. Most of what I see is cannabis," the judge said. He put additional conditions on her sentence of six months' supervision with activities, including that she adhere to home curfews, does not associate with co-offenders, engages in activities and programmes, does not consume alcohol or drugs and gets counselling.

The judge warned her she would be going to the adult court and prison if she breached her conditions, stressing that a prison sentence for class A drug dealing would ordinarily be given.

"Offering to supply LSD to others in the community your age is absolutely unacceptable and I need to send a strong message to all teenagers that it's so serious that prison will usually result."

The judge ordered the girl to return to court on December 13 so a six month supervision order could be imposed to follow the current sentence.

- © Fairfax NZ News