The Fletcher-based athlete has been selected in the team at only 15 years of age.

She will train and race with the team over coming months and then likely be included in a squad of five or six to attend the world junior championships next year.

Monk's coach Gerrard Keating said the selection was a "shock" but was a reward for her dedication in training and string of commanding results earlier this year.

"It's fantastic for Montana," he said. "They obviously saw something from her at the NSW titles. It was a shock to me that they even selected this, this early, which is great.

"The women's 4x400 team could do quite well at world juniors next year, and they've probably looked at her because of her 800 metres as well.

"She flies under the radar a little bit, but she's a massive talent. Her 400m times have been dropping."

Keating said it was likely Monk would form part of a squad that travels to the 2020 IAAF World U20 Championships in Nairobi, Kenya.

"They've got these four girls together to have a look at them and see what they can produce," he said. "Montana's the youngest by probably two years.

For world juniors you have to be 16, so she falls into that because she turns 16 next year.

"It will be good for her to be in a relay for her first one," Keating said. "That's how Cathy Freeman started, she made her first Australian team in a relay. Sally Pearson - made her first Australian team in a relay.

"Particularly when they're young, it's a good stepping stone for them."

The championships will be staged in Kenya July 7 to 12.

Athletics Australia said the championships "represent an important development opportunity for athletes within the pathway".

Monk joined Keating's training about two years ago with the coach crediting her dedication to training.

"Every session she does is just quality," he said. "I've never seen somebody whose training is just so consistently of high quality, there's never any dip. She really does train like an elite senior athlete."