Despite the small margin of victory, the hosts and holders always looked in control of the match between the regional rivals at Melbourne's Junction Oval.

The game was a straight shoot-out to decide who joined India in the last four from Group A and it was the four-time winners who prevailed thanks to superb displays from Beth Mooney and Georgia Wareham.

Opener Mooney scored 60 with the bat after New Zealand won the toss and elected to field.

Her innings came from 50 deliveries and included six fours and two sixes as Australia ended on 155-5.

In reply, New Zealand struggled to get going and were always behind the required rate as Wareham took 3-18 with her leg breaks.

Katey Martin did provide some late fireworks with the bat, scoring 37 from 18 balls, but it was too late as her side came up just short.

"It was a crunch game, we handled it really well," said Australia captain Meg Lanning.

"I think we showed that we are able to be calm under the pump, we have done the basics right which gives us confidence going into the semi-final."

In the other Group A game, Sri Lanka eased home against Bangladesh by nine wickets as both sides attempted to end their tournament with a first win.

After electing to bat, Bangladesh struggled to 91-8 as Sri Lanka's Shashikala Siriwardene impressed by taking 4-16.

Hasini Perera ended not out on 39 as the target was easily chased for the loss of one wicket.

Group B will conclude tomorrow, with South Africa and England already confirmed as semi-finalists.

South Africa will win the group and play Australia in the last four if they beat West Indies.

Pakistan will meet Thailand in the other clash.

Both games are at Sydney Showground Stadium.