Former skipper Sharelle McMahon says the Diamonds' constant experimentation makes it tough for archrivals New Zealand to formulate a game plan to beat them at the world netball championship.

Defending champions Australia have played vastly different line-ups in their pool games as they build towards Sunday's grand final at the Singapore Indoor Sports Stadium.

McMahon warned however that the rotation of players could also work against the Australians.

"The danger is not allowing the team that you do finally settle on enough time to work together and have that really deep understanding of each other," said McMahon, who is commentating on Australia's matches with ABC radio after being ruled out by the ruptured achilles tendon she suffered in late March.

"The danger of having quite a set seven is that if you do need to make changes the ones on the bench maybe don't come on as well.

"I think the ability to really change it up with completely different players out there and different styles is a benefit more than anything."

In Australia's 75-33 win over Northern Ireland, coach Norma Plummer at one stage opted to play Natalie Medhurst at goal shooter and Erin Bell at goal attack - a combination she wouldn't use against a powerhouse team like the Silver Ferns.

"New Zealand wouldn't have got too much out of that because I don't think it's something we're going to see too much," said McMahon.

"It will be really hard for the opposition to get a handle on who's going to be playing and where they're going to be playing."

McMahon, who has played 118 Tests, skippered Australia to win the crown at the last world championship four years ago in Auckland, beating the Silver Ferns in the grand final.

She believes the Australians, who have seven players at their first world championship, are on track for a successful title defence and liked the extra height newcomers like defender Sharni Layton and holding shooter Caitlin Bassett have brought to the side.

"I definitely think they can win and they showed that when they beat New Zealand over there," said McMahon, who hasn't made a decision on her playing future.

She named England, who the Kiwis are in line to play in the semi-final on Saturday, as the dark horse.