The White Ferns' World Cup campaign is back on track with tomorrow's clash against the West Indies looming as crucial.

New Zealand thrashed tournament upstarts Sri Lanka by eight wickets yesterday in their first Super Six encounter.

The result lifted them to second place on the points table behind unbeaten Australia.

But they are just ahead of the West Indies on run rate and get a chance to extend that advantage when they meet in Mumbai tomorrow night.

New Zealand then have a tricky assignment against struggling defending champions England on Wednesday where a place in the final is likely to be on offer.

In other matches yesterday the Windies beat South Africa by two wickets and Australia edged England by two runs.

But it was the White Ferns who flexed their muscles at the right time with an emphatic victory against a Sri Lankan side full of confidence after earlier wins against England and India.

Opening bowlers Sian Ruck (3-60) and Lea Tahuhu (4-27) led the way as New Zealand dismissed Sri Lanka for just 103 in 42 overs.

The Kiwis then rattled off the required runs in 23 overs with Frances Mackay (39 not out), Suzie Bates (37) and Sophie Devine (29 not out), cruising at the crease.

"We came out and we expected a really tough game against an improved Sri Lankan side," New Zealand skipper Bates said, happy to collect a comfortable two points.

Having shifted to Mumbai from Cuttack where they beat South Africa and Pakistan but lost to Australia in group play, the New Zealanders took an instant liking to the new conditions and will feel comfortable there as the tournament plays out over the next week.

"After we won the toss [yesterday], it was difficult [for them] in the morning in varying conditions first up. We got early wickets which put them on the back foot," Bates said.

"It was easier than we had perhaps planned for, so we are really happy with the win."

The Sri Lankans conceded they couldn't cope with the pace and swing of the New Zealand attack.

Tahuhu struck with her first ball, bowling Yasoda Mendis, who had scored heavily in Sri Lanka's two victories in the first round.

Sri Lanka never recovered as the New Zealand bowlers made the most of the lively conditions. Off-spinner Mackay chipped in with 2-18 for a fine allround effort.

But Canterbury's Tahuhu was the star and appropriately won the player of the match award.

"It was a really nice pitch to bowl on to be honest, especially after winning the toss.

"There was a bit of swing and it was really nice to get those figures," Tahuhu said.

In tonight's games, Australia play Sri Lanka and England play South Africa.

- © Fairfax NZ News