By Jonathon Moore Rugby union editor

Jonah Lomu will continue his dialysis treatment

All Black scrum-half Justin Marshall says Jonah Lomu could yet win his battle against a rare kidney disease and appear at the Rugby World Cup.

Lomu, who will make his return for Wellington this weekend, began dialysis just three months ago and faces a tough challenge to prove his fitness to All Black coach John Mitchell.

But according to Marshall, Lomu is firmly on his way to making his international return.

"I spoke to our team doctor today, who deals with all of Jonah's medical problems, who thinks he's looking really good," Marshall said.

"He looks a lot better than he's ever been and that's great for New Zealand rugby.

"Obviously Jonah's been carrying his problem for a while and he's very keen to play."

He's a person who started playing because he enjoyed it and he doesn't feel like he's played long enough Justin Marshall on Jonah Lomu

The 28-year-old will face Taranaki in Wellington's final warm-up match on Saturday and Mitchell has by no means ruled out a Lomu return, saying: "The door is still open, we don't pick our team until 25 August."

Marshall added: "Jonah's a proud All Black and I know how much he values the jersey.

"He's a person who started playing because he enjoyed it and he doesn't feel like he's played long enough yet, so he just wants to get out there and play."

New Zealand could wrap up the Tri-Nations title on Saturday against a South African side criticised for their discipline problems.

The Springboks had two players yellows carded against Australia last weekend in a match that left Aussie number eight Toutai Kefu with spinal concussion.

South Africa forwards Robbie Kempson and Bakkies Botha were both handed bans after the match.

But Marshall said suggestions that the Springboks are 'out of control' are premature.

"I think it was just one of those games and unfortunately it carried on off the field with both teams complaining about each other's tactics," he said.

"We're not phased about it and we'll just carry on and play the way we've been playing."