The quest for just the second Constellation Cup clean sweep and a more complete performance, will drive Australia in the final match of the series in Sydney on Saturday.

The Diamonds took an unassailable 3-0 lead in the four-game series with a 55-43 win over New Zealand in Adelaide on Wednesday night.

It was the seventh time in the eight years of the competition they have held the trophy, but only in 2014 were they able to sweep the Silver Ferns.

"We may have won the Constellation Cup now, but we want to finish four-zip and that's what we're going to aim to do," Diamonds' wing attack Liz Watson told NZ Newswire.

Silver Ferns coach Janine Southby said they were not up to it.

"You don't step at this level, you don't break at this level.

"You've just got to cut those basic errors out and we know the passing the places we're getting into trouble and we still persist  in passing into them and it's not good enough at this level."

Despite that, Southby insisted there was some light in their display last night.

"Scoreline aside, there was some very pleasing aspects to tonight's game compared to what we've done in other games, particularly defensively."

Captain and defender Katrina Grant says motivating her side for game four won"t be hard even though the match was effectively a dead rubber.

"You do not want to go four-nil down," Grant told the Nine network.

"The desire is there for us and we want to win this game."

Diamonds; coach Lisa Alexander says her team needs to lift their game.

"We want more," Alexander said. "This group really wants to perform at its absolute best in Sydney over four quarters."

While Australia won the second and fourth quarters in Adelaide 18-9 and 17-9 respectively, they were outscored 15-8 in the third.

"We just lost our way and went away from our game plan in that third quarter," Alexander said.

She was disappointed Australia had problems bringing the ball out of their defence end after winning precious turnovers.