The girl, believed to be a 15-year-old from Sydney, collapsed and stopped breathing inside the festival grounds about 2.30pm on Saturday.

Nearby paramedics were able to perform CPR on the girl to revive her before she was taken to John Hunter Children's Hospital in a critical condition, the Newcastle Herald reports.

Her condition improved overnight on Saturday, and she had regained consciousness and was talking to worried family in hospital on Sunday morning.

Detectives were due to speak with the girl late on Sunday, as well as asking her about the significant amount of substances allegedly found in her clothing as emergency services frantically cut them to save her life.

"If the paramedics had not been so prompt with treating her she wouldn't be with us," Central Hunter crime manager Detective Inspector Mitch Dubosjki said.

"If she was on the street instead of next to these guys, she would be gone."

The girl was one of at least two teens who were hospitalised following suspected overdoses, with a boy being discharged from Maitland Hospital on Sunday after being treated.

Another festival-goer was treated for bad effects of drugs.

And a further 36 people were detected by police dogs trying to carry drugs, mainly MDMA, into the festival.

"It is disappointing, and the vast majority of them are juveniles," Detective Inspector Dubojski said.

"That is very concerning.

"We continually warn people of the dangers of using these substances but the message doesn't seem to be getting through, they just don't want to hear it."

Festival organisers appeared to have washed their hands of the troubles surrounding sections of the 20,000-strong crowd, refusing repeated calls for comment about the near-death of one of their patrons.

Despite knowing the girl had been taken away and was fighting for her life in hospital, the organisers said on its Facebook page: "Thank you Maitland that was an epic start to our tour".

They continued to tweet photographs of the event on Sunday, but failed to post anything about the overdoses or drug charges.

Saturday was the first leg of the Groovin' the Moo festival, which describes itself as Australia's only regional touring music festival.

The Maitland event was the first of six events held at various regional centres.

In the past year, seven people have died after allegedly overdosing on drugs at music festivals across Australia.

The Newcastle Herald