A child protection group says a girl who revealed on radio she was raped should be praised for breaking "the silence on child sexual assault".

The 14-year-old girl was strapped to a lie detector during 2Day FM's Kyle and Jackie O breakfast show on Wednesday because her mother was concerned about her behaviour.

When her mother asked if she was sexually active the girl replied: "I've already told you the story about this ... and don't look at me and smile because it's not funny."

Raising her voice she then said: "Oh, okay, I got raped when I was 12 years old."

Host Kyle Sandilands responded by saying: "Right, is that the only experience you've had?" before the interview was brought to an end.

The segment has set off a storm of criticism, while NSW Police and the state's Department of Community Services (DoCs) are investigating the sexual assault claim.

However, child protection advocacy agency Braveheart praised the girl for telling the truth.

"Sexual assault is disempowering...," founder Hetty Johnston said in a statement on Thursday.

"But this little Braveheart reached into her 'self' and found potentially, the last shred of 'self' power she possessed, and told everyone the truth...

"There are so many issues around this but the bottom line is that this 14-year-old stunned the nation with the truth.

"She broke the silence on sexual assault."

The Association of Children's Welfare Agencies called the on-air incident "irresponsible media", a view shared by NSW Community Services Minister Linda Burney.

She said her office was inundated with calls over the interview and DoCs had now met with the girl and her family.

"Let's hope this is a sober lesson to that particular radio station and other such radio stations that think stunts like this are acceptable," she told reporters on Thursday.

"Whether or not they knew the claim of a rape is irrelevant.

"The fact they had a 14-year-old girl there, asking her about sex, is the focus and the inappropriate action here."

She said she felt sick when she heard a replay of the interview, but the question of whether the radio hosts should be sacked over the incident was up to 2Day FM management.

In June, ABC television's The Chaser's War on Everything program was taken off the air for two weeks after a skit about fictitious dying children offended viewers.

Deputy Prime Minister Julia Gillard believes the top consideration should be the welfare of the girl.

"Can I say on that matter, I think there's only one really important thing here, and that really important thing is the welfare of the young girl involved," Ms Gillard told reporters in Sydney on Thursday.

"I would say to Kyle that he should be thinking through what is in the best interests of the welfare of that young girl."

Sandilands and Jackie O have denied the interview was a set-up, as suggested by some media commentators.

"There is no way we would have wanted to put that girl in that situation," Jackie O said in their show on Thursday.

"It was one of those moments. When live radio happens, sometimes you are lost for words."

The Australian Communications and Media Authority (ACMA) said it had received about 30 complaints related to the segment by noon (AEST) on Thursday.

"We've advised those people in the first instance to write to 2Day FM," ACMA spokesman Donald Robinson told AAP.

"If they are not satisfied with the response they can bring their complaint back to us and we will investigate it to determine if there had been any breach of the commercial radio code of practice."

Belfast Telegraph