Chair of the committee, NSW Liberal Senator Hollie Hughes' questioning of a Tasmanian autistic adult and advocate - including Phillip StEvens - left them in need of consoling afterwards as she vigorously argued in favour of ABA, a framework that has the goal of improving challenging behaviour.

"I find your approach offensive, particularly with your being the chair. Your bias is obvious," Mr StEvens said.

"It's not bias, it's best practice," senator Hughes responded.

"It is bias, and you're speaking over me, which is outrageous," Mr StEvens said.

"Well, I find you outrageous. I'm done," the senator concluded.

Senator Hughes is the mother of an autistic child and has become an advocate of ABA after experiencing "huge results" in her son's behaviour using a "play-based positive reinforcement program", but the practice encounters opposition from members of the autistic community who regard it as trying to "fix" children by using methods seen as demeaning and harmful.

Mr StEvens told the committee that he believed ABA was akin to "dog obedience training" and that he was aware of people who were "traumatised" by it, while accepting that its use could be appropriate in some cases. Autism advocate Geraldine Robertson said she started training in ABA but "gave up in disgust".

Senator Hughes describes ABA as "the government's own best practice recommended therapy" and regularly criticises opponents using her social media - a confrontational approach that materialised in Launceston.

In Tasmania, access to ABA is limited to a small number of private clinics, with Leaps Ahead in Glenorchy one of the few that offers the service.

Clinical director Michelle Furminger - Tasmania's only board-certified assistant behaviour analyst - said ABA wasn't specifically a therapy, but was a combination of a range of methods to "teach a child to learn how to learn".

"We make individualised programs that work on specific needs of the child," she said.

"This is done by analysing the child's current skill set to identify their strengths and deficits and to understand the challenging behaviours that are barriers to learning. Behaviour analysts can use a number of therapeutic styles based on the science of ABA to teach functional skills and increase the child's capacity to be independent."

It was also heavily data-driven, Ms Furminger said, and used elements of reinforcing improved behaviour.

"Behaviour analysts are able to break skills down to the simplest level to ensure that the child can learn any task. Positive reinforcement is used so the child experiences success with their learning," she said.

"Behaviour analysts focus on the whole learning environment and experience to see how the child's learning can be maximised from the instructions given, material used or reinforcers provided."

The clinic also provides ABA to children without an autism diagnosis, and advocates for greater access and training of therapists in the field.

Autism Tasmania is well aware of the ongoing debate within the autism community around ABA and believes that, locally at least, discussion has been respectful and parents are entitled to make their own decisions.

Chief executive officer Donna Blanchard said she was taken aback by the senator Hughes's approach, which she described as "out of line", while also acknowledging that the senator had clearly been through many challenging experiences as a parent.

"The issue for me was for the senator to continue saying that the 'evidence is there, don't you agree?' That's quite abhorrent language, because the evidence has never been endorsed adequately, the evidence is still only emerging," Ms Blanchard said. "We need to be able to say with empathy, yes, that was her experience with her child.

"Let's not shy away from the fact that autism embraces a whole range of neurodiversity, expresses itself in unique ways, and some of those mean that the person is quite disabled, their behaviour is unusual and might not be safe to themselves or indeed the community.

"But senator Hughes is talking about the 'some', and not the 'all'. We're dismissing and diminishing the focus. This is not a senate committee into highly-disabled people with autism, it's a senate committee into autism."

During the hearing, senator Hughes stated that ABA was globally-recognised as best practice. She said it was "personalised" for when parents are working towards things like toilet training and independent dressing, and was critical of those who dismissed ABA after only looking into web-based training modules.

The internet is awash with papers arguing for and against ABA, while some claim the long-term effects of the therapies are yet to be studied in sufficient detail.

Yet on the ground, concern among parents of autistic children appears quite common.

Meredith Lockheed is the mother of two young autistic boys and has, in recent years, become somewhat of a facilitator for Tasmanian parents looking for support and community connection.

She said she could "see the appeal" of ABA for parents "willing to do anything to have a normal child", but the vast majority of parents in the autism community had concerns.

If the Senate select committee resulted in a push for more funding and emphasis on ABA, Ms Lockheed said there would be "extreme backlash".

"ABA will say it's reward-based so it's different, but if you're only addressing their behaviour and not their needs, you're not addressing the child as a whole," Ms Lockheed said. "Instead of teaching autistics their sensory needs and meeting them, it's teaching them to mask their autistic selves to be accepted into society.

"Of course there are going to be cases of behaviour that are unaccepted to society, or dangerous to others. But if you think about what it is that's actually causing those challenging behaviours, it's something sensory or emotional that's causing it. They don't do it for the fun of it, something is causing it."

She said it was up to parents to make their own decisions about what was best for their child.

"It comes down to trusting your gut. If your child is uncomfortable, or you're uncomfortable, it's OK to try something else," Ms Lockheed said. "At the end of the day, my job as a parent of a child who doesn't have a voice is that I want what's best for him. That's not to change him or to mask his behaviour."

The Senate select committee has finished its public hearings and is expected to report in March.