New Zealand kept their pursuit of a Women's T20 World Cup semi-final berth alive with victory over already-eliminated Sri Lanka in the heat of daytime Sharjah.

Set a target of 116 to win, New Zealand comfortably chased it down in 17.3 overs but may rue not having the power and positivity to get the job done sooner.

New Zealand’s inferior net run-rate remains a potential barrier to their progression ahead of India after they were unable to accelerate quickly enough to a potentially decisive victory.

Opener Georgia Plimmer and all-rounder Amelia Kerr took a while to get going but batted beautifully in a partnership of 46.

Earlier, Sri Lanka captain Chamari Athapaththu found form for the first time in a disappointing tournament to score 35 from 41 balls but her side's threat left with her.

Sri Lanka did at least reach triple figures for the first time in their four matches but were unable to create chances with the ball in punishing temperatures touching 39C.

New Zealand remain third in Group A behind Australia and India, while winless Sri Lanka stay bottom.

But much will depend on Sunday’s meeting between Australia and India - where a win for India would keep them in pole position because of their still superior net run-rate.

New Zealand needed to reach their target inside 15 overs to move ahead of India on net run-rate but captain Sophie Devine said the team did not discuss that target.

"We actually didn't [talk about the run rate], to be perfectly honest," she said.

"We set targets at the innings break and that was always to get us to win in the 17th or 18th over, but we know that winning the game is the most important thing.

"We will see how results play out on Sunday and then by the time of our final game against Pakistan we will know exactly where we stand."

New Zealand struggled with the ball early on, some erratic bowling from Rosemary Mair abetting Athapaththu’s fluid knock.

The Sri Lanka captain hit five boundaries but the run rate was never too scary, and once Athapaththu was bowled trying to step on the accelerator her side collapsed somewhat.

A run of two wickets for five runs in 15 balls put the brakes on as excellent control from Kerr and a fine catch from Devine brought the game back into New Zealand’s control.

New Zealand were slow to reply initially, only hitting their first four off the 25th ball of the innings, but once Plimmer found the fence the opener was able to cut loose.

Plimmer was put down on 33 by Inoshi Priyadharshani - a difficult caught and bowled chance - and made Sri Lanka pay, moving to her half century in 41 balls with a flurry of crisp shots down the ground.

Plimmer holed out to deep square shortly after but Devine came in and ended the match with the first six of it.

Sri Lanka captain Chamari Athapaththu: "We have not played our best cricket in this tournament, we needed another 25-30 runs on this surface. Our bowlers did their best but it wasn't enough."

Player of the match, New Zealand opener Georgia Plimmer: "It's about being aggressive and just being able to play my brand of cricket.

"Sometimes it might not come off but if I can get the team off to a good start like that I am happy."