Former Black Ferns captain Les Elder may have missed out on the Rugby World Cup squad, but she was still passionately supporting the team from the sidelines.

Elder, who captained the Black Ferns during their tour to Europe last year, was one of several big names to miss selection for the World Cup.

But that didn't stop her from performing the Black Ferns haka with her former team from pitch side ahead of New Zealand's opening World Cup victory over Australia at Eden Park over the weekend.

Elder, who is part of the broadcast team covering the World Cup for Spark Sport, was recorded joining in on the haka, with the video being shared across social media.

British rugby journalist Laura-Jane Jones took to Twitter to share the moment.

"The highlight of yesterday for me was the @BlackFerns Haka," Jones said.

"In my years covering women's AND men's tests, I can easily say that was the most powerful I've ever witnessed.

"The amazing Les Elder was next to me pitch side and joined in too. Once a Black Fern, always…"

One fan added: "You can take the Black Fern out of the game but you can't take the Black Fern out of the heart."

Another labelled Elder's sideline haka "stunning".