When Georgie Stone learned transgender adolescents will no longer need court approval for treatment to change gender, she cried "happy tears".

"It was just like an explosion of all these emotions. Just absolute relief," the Melbourne 17-year-old said.

After considering the case of 16-year-old "Kelvin", the Family Court of Australia ruled on Thursday that adolescent Australians seeking hormone treatment to change gender can do so without a judge's order.

The change allows for stage two treatment that "may, but does not necessarily, cause long-term infertility" and stops short of surgical intervention, the court noted.

Georgie - a transgender advocate recently crowned the 2018 Victorian Young Australian of the Year - knows firsthand the stress of going through the court process.

Georgie Stone (L) has cried 'happy tears' after learning gender patients won't need a court order. Photo: AAP More

Born a boy, she became the youngest person in the country granted permission by a court to take hormone blockers, the first stage of medical treatment for transgender children.

By 2013 court permission was not needed for transgender children wanting the first stage of treatment. But Georgie still had to return to the court to ask for permission for stage two.

"To have a complete stranger decide what was going to happen to my body was horrible," she recalls.

"I wasn't going into female puberty, I didn't like my body, and I felt really powerless and on top of that, mental anguish.

"Having to go to court is very time-consuming and costly as well. We were lucky because we had pro bono lawyers but lots of families don't."

Thursday's landmark case centred on Kelvin, who was born a girl and confirmed as having gender dysphoria by age nine.

His parents applied to the court in early 2017 asking that he be deemed competent to authorise his own stage two treatment which would involve having testosterone to initiate secondary sexual characteristics and appearance of the male sex.

"For Kelvin, if stage two treatment was not carried out his overall health and wellbeing is almost certain to deteriorate especially as his mental and physical health is heavily dependent on the perception of himself as male," Thursday's decision noted.

Australia is the only country in the world that requires court involvement in stage two decision-making.

Melbourne's Royal Children's Hospital, which was a party in favour of the changes in the Family Court case, welcomed the decision.

The hospital's Dr Michelle Telfer said for the first time, transgender adolescents will now have the same rights to healthcare as their peers, noting that in the past many young people postponed treatment until adulthood to avoid having to go to court.

"These young people are healthy, they're young people often with a strong sense of justice, of doing the right thing, pillars of society often," she said.

"To think that they might have to go to court just to ask for treatment is quite a stressful situation to be in."