New Zealand salvaged an unlikely victory against Bangladesh Saturday to set up a crunch clash against Australia for a place in the women's T20 World Cup semi-finals, as impressive India kept their unbeaten record intact.

Coming off a narrow loss to India, the White Ferns won the toss and opted to bat on a slow Junction Oval pitch in Melbourne.

But after reaching 66 for two they collapsed to 91 all out, as Ritu Moni grabbed a tournament-best 4-18 with back-up from fine fielding.

A first World Cup victory for Bangladesh since 2014 was within reach, but they blew the chance with sloppy batting and poor running between the wicket seeing them bundled out for 74.

"Obviously nowhere near what we wanted to post today, but Bangladesh were fantastic, they put us under pressure on a really difficult wicket," said New Zealand captain Sophie Devine. "We learned from what Bangladesh did, bowling straight and making the batters make mistakes and then we know what our spinners can do."

India had already qualified for the semi-finals and a decisive seven wicket win over Sri Lanka in Melbourne ensured they completed their Group A games unbeaten.

New Zealand and defending champions Australia both have two wins from three, making their Monday clash in Melbourne a quarter-final. Bangladesh are eliminated after losing three from three.

Good line and length from Bangladesh's bowlers restricted openers Devine and Rachel Priest to just 23 from the first five overs.

The runs started flowing but Devine fell to spinner Salma Khatun on 12 while trying to force the pace. Priest soon followed, lbw for 25, to leave them at 40 for two in the ninth over.

Experienced campaigner Suzie Bates' departure for 15 sparked a collapse, with the rest of the wickets falling for just 25 runs.

Bangladesh began the chase well, moving to 17 without loss before Kasperek snared Murshida Khatun for 11 then Hayley Jensen removed Ayasha Rhaman, leaving them on 19 for two.

In the later game, Sri Lanka won the toss and chose to bat, losing an early wicket before captain Chamari Atapattu steadied the ship with an entertaining 33 before holing out to square leg, a ball after hitting Radha Yadav for six.

Kavisha Dilhari chipped in with a breezy unbeaten 25 in their 113 for nine, but India's spinners were the stars of the show, led by Yadav who took a career-best 4-23.