South African captain Dane van Niekerk and Gardner's Sydney Sixers teammate and Southern Stars wicketkeeper Alyssa Healy say the hard-hitting all-rounder is ready to represent her country.

The Indigenous women's captain and Australian second XI representative has emerged as one of the world's best T20 players this season, belting 393 runs and a competition-high 13 sixes in the Big Bash, to go with her 10 wickets.

Her destructive form has been a huge factor in the Sixers' run to Saturday's WBBL final against the Perth Scorchers at the WACA Ground.

Van Niekerk, who has just returned from captaining South Africa in a five-match ODI series in Bangladesh, said Gardner was an obvious choice for Australian selectors next month.

"It'll be funny if they don't pick her to be honest," van Niekerk said. "They can't go wrong with Ash.

"Besides the fact that she can blast a ball into the stands and she's been scoring runs consistently at a very high strike rate, she offers you really good bowling and fielding options, which is the complete package in my opinion, especially in T20 cricket.

"I heard about her last year, but I never saw her ... Ash Gardner's a well known name at this stage in the competition and she's really made a name for herself. She's just showed us who she really is.

"She's got a great future ahead of her, especially being so young. She carries herself really well. Sometimes I have to check if maybe I am older than her, because she carries herself a lot better than I do."

Van Niekerk knows a thing or two about playing international cricket at a young age. She was drafted into the South African team as a 15-year-old and took the captaincy reins eight years later at the age of 23.

The Southern Stars play T20s against New Zealand next month in Melbourne, Geelong and Adelaide.

Healy will be one of the first names on the team sheet after an impressive WBBL, a swashbuckling 77 against Hobart in the semi-final on Wednesday her latest contribution.

"I wouldn't be too surprised if she gets a phone call in a couple of days to play against New Zealand," Healy said of Gardner.

"She's probably been the most in-form batter in this whole tournament. I hope she does get that opportunity. She's come a long way in the last 12 months, she's really focusing on her cricket and working really hard and it's really exciting to see."

Healy will captain the Sixers on Saturday in the absence of Ellyse Perry, who will miss the final with a hamstring injury.