Two of the top-ranked players on the WTA tour have spoken about world number one Ash Barty's shock retirement, with Danielle Collins calling it "badass".

Barty announced she had retired through a post on her Instagram account, where she had a sit-down interview with former Australian tennis player Casey Dellacqua about her decision to walk away.

In her interview, Barty discussed accomplishing the goals she set out for herself in her tennis career, capped off with wins at Wimbledon and this year's Australian Open, as well as having other dreams she would like to work towards.

Barty, 25, has played professional cricket in Australia's Big Bash League, and has been linked with her beloved Richmond Tigers if she were to try her hand at Australian Rules football.

She is also recently married, and has discussed her desire to start a family.

Collins, currently the world number 11, spoke about how incredible it is that Barty is able to walk away at such a young age, with so many accomplishments under her belt.

"I am a little bit surprised because I think at 25 and being at the top of her game and in achieving everything that she's achieved and being so young she would certainly continue to achieve what she's been achieving," Collins said.

"But I think it really speaks to the way that our game empowers women, because how many other professions would you be able to retire at 25?

"I mean, this is incredible, it's so badass, and I really have a lot of respect for Ash making the decision to do what's best for her, and to live out her life on her terms. It's really special."

Rising star and world number two Iga Swiatek also weighed in, saying her first reaction was an outpouring of emotion about what a loss it was for the game of tennis.

"Well, I mean, it is so fresh and it's so sudden that it is something that I need to digest," the 20-year-old said.

"I cried for like 30 minutes, actually, when she posted that video and that interview.

"It's very hard to describe it because on one hand… if you know Ash, it's not a surprise at all, because she's like that kind of person who's looking for challenges also in other aspects of life.

"I mean, you can see that she's pretty confident with her decision. But on the other hand, it's new for me to see athletes retiring so early.

"I'm pretty new on tour and I feel like I wanted to play more matches against Ash, and also compete against her and have a chance to actually understand how she plays and how she uses the different skills that she has.

"I mean, for me, I feel kind of sad that I'm not going to be able to do that because I think it would be a great rivalry. And also, she's a great person to look up to and to kind of chase.

"But I'm also happy for her, and I think she's really brave that she made that decision because there would be many people who, I don't know, kind of stay in this place because you were first in the world.

"But if you're not feeling happy with what you're doing or if you're feeling satisfied as she did after winning the Australian Open, then it's your own decision. And I think she's pretty brave that she made that decision."