One of seven players to sit out Australia's semi-final win over Papua New Guinea this week, Johnston has been named to return against New Zealand at Old Trafford in the showpiece match, set to kick off at 12.15am (AEDT).

"I've been ill the last few days so I'm looking forward to getting out there for our captain's run," Johnston told the Newcastle Herald from Manchester two days out from the final.

"It's obviously difficult missing games but unfortunately I was unwell.

"But my body is probably a little bit run-down as well, so it was good for my body to get that rest and recuperate myself for the final."

Johnston, 21, had played a prominent role for the Jillaroos up until missing the semi-final, starting two pool matches in the front row and scoring a try on debut.

The Belmont product has been named to start in the final and is eager to make an impact early.

"I can't wait," she said.

"It's going to be a tough game for us, especially in the middle, but if we can get our jobs done in the middle it will make it a lot easier for those on the outside.

"Hopefully we win that World Cup on Saturday night."

Johnston won't be the only Knights player involved.

Back-rower Yasmin Clydsdale was named in Australia's side. Autumn-Rain Stephens-Daly lines up for New Zealand, while Raymond Terrace-based Shanice Parker appears to have failed to overcome a knee injury after being left off the Kiwi Ferns' team-sheet.

Australia, who have won the past two World Cups, beat New Zealand 10-8 last week in the final round of pool matches in what was a highly competitive clash.

Johnston said she was expecting New Zealand to have taken plenty of confidence out of the match and to be desperate to secure their first World Cup title since 2008.

"They're tough, driven people," she said.

"They've got a straight-forward, hard mindset.

"They definitely put it to us through the whole 80 minutes. There were errors we made that we've tried to fix.

"Hopefully we can improve from that game, but it's going to be a tough one."

Johnston, a Windale Eagles junior who proved in 2022 she is one of the game's leading props winning the NRLW with Newcastle and Origin with NSW, said the Jillaroos would try to tactically outplay their Tasman rivals.

"We need to play smarter, not harder," she said.

"We need to work on what went wrong against them in the [pool] game and I think that's something we've worked towards. We just need to be on the ball."

On the thought of winning a World Cup, Johnston said there would "definitely be some great celebrations after and a few bevvies."

"I always dreamed of being here and wearing the green and gold jersey," she said.

"We've only got a few days left here in England, so I'm just going to soak it up and enjoy it and hopefully we bring that World Cup home."