A double-century opening stand carried tournament favourites Australia to a commanding 157-run win over the West Indies on Wednesday and a place in the Women's World Cup final.

Australia dominated their rain-shortened semi-final in Wellington from the outset, built around a 216-run stand -- the highest of the tournament -- between experienced openers Alyssa Healy and Rachael Haynes.

An imposing score of 305 for three off a reduced 45 overs was never threatened by the West Indies, who succumbed for 148 in the 37th over.

The six-time champions Australia are unbeaten at the 50-over tournament and will face either South Africa or 2017 winners England in the final in Christchurch on Sunday.

Play started nearly two hours late because of misty rain and Healy, in particular, struggled for timing in the early stages after Australia were sent in on a damp Basin Reserve pitch.

She accelerated as the sun came out, posting 129 off 107 balls to register a fourth one-day international century and fell four runs short of her career-best score.

The wicketkeeper-batter used her feet to excellent effect against the spin-based Caribbean attack, smashing 17 fours and a six.

She didn't hit a boundary until the 12th over but said Haynes had reminded her to remain patient.

"I hope I've learned my lesson by now, that it doesn't necessarily have to happen all at once," Healy said. "I love batting with Rach, she's a calming influence."

Haynes compiled 85 off 100 balls while the late runs came via unbeaten knocks from captain Meg Lanning (26) and Beth Mooney (43).

- Dropped catches -

It was a disappointing performance from the sixth-ranked West Indies, who were loose in the field, dropping a handful of chances, and they struggled for momentum with the bat.

Captain Stefanie Taylor was their top scorer with a careful 48, but she lacked support after top-order pair Deandra Dottin and Hayley Matthews both departed for 34.

Their hopes weren't helped by injuries suffered in the field to bowlers Chinelle Henry and Anisa Mohammed, with neither able to bat, meaning Australia needed to take only eight wickets.

Taylor said her players felt like they were on the back foot from the outset as Healy and Haynes established themselves.

"A partnership like that deflates the team and, the pressure they applied, we couldn't get over that," she said. 

"When you looked up, they were 100 without loss and all the dropped catches didn't help us."

Lanning was relaxed that her team weren't pushed to the limit.

"I've been involved in some very stressful semi-finals in the past and we came in expecting a very difficult game," she said.

"The West Indies bowled well at the front and put us under pressure but it was a good game plan we had, to build a good base."

The second semi-final pits defending champions England against second-ranked South Africa in Christchurch on Thursday, a repeat of the 2017 last-four thriller that was decided in the final over.

Scores

Brief scores from the women's Cricket World Cup on Wednesday as Australia beat the West Indies by 157 runs in a rain-shortened semi-final in Wellington:

Australia 305-3 in 45 overs. (A. Healy 129, R. Haynes 85, B. Mooney 43 not out; C. Henry 2-51)

West Indies 148 all out in 37 overs (S. Taylor 48, D. Dottin 34, H Matthews 34; J Jonassen 2-14)