India sent out a warning to their rivals at the Women's World Twenty20 with a 48-run thrashing of record three-time winners Australia in Guyana on Saturday.

Smriti Mandhana and Harmanpreet Kaur starred with the bat as the Indians racked up 167-8 batting first, before restricting Australia to 119-9 as wicketkeeper Alyssa Healy suffered concussion and could not bat.

India, last year's World Cup runners-up, topped Group B after four straight wins and will face either England or reigning champions and hosts West Indies in the semi-finals.

Mandhana hammered 12 boundaries, including three sixes, in a 55-ball 82, putting on 68 for the third wicket in just seven overs with captain Kaur, who smashed a quick-fire 43.

"We were very happy with the way we fielded," said Kaur. "Smriti and I always enjoy playing together and we hope we have more of those sorts of partnerships."

It was a disappointing performance from Australia, as they struggled against India's spinners, with Anuja Patil taking 3-15 and Radha Yadav claiming 2-13, including the vital wicket of Meg Lanning for just 10.

Captain Lanning was optimistic that key batter Healy would be fit for the last four.

"We'll have to look after Alyssa and hopefully she'll be all right for the semi-final," she said. "Today showed we've got a lot to work on — we'll have to play a lot better to get through the semi-finals."