Australian opening batters Beth Mooney and Alyssa Healy took the defending champions to a dominant 10-wicket Women's T20 World Cup win against Sri Lanka at St George's Park in Gqeberha on Thursday.

The victory puts Australia on six points and within touching distance of the semi-finals, while Sri Lanka's chances of making the final four will likely hinge on if they beat New Zealand in their last group game.

Sri Lanka were restricted to 112 for eight after being sent in to bat in overcast conditions.

Grace Harris and Megan Schutt were mainly responsible for Sri Lanka's moderate batting performance, although all Australia's bowlers were economical on a slow pitch.

Harris ran from mid-on and took a spectacular diving catch off Ellyse Perry to end an aggressive innings by Sri Lanka captain Chamari Athapaththu (16) to effect Australia's first breakthrough with the total on 30.

Sri Lanka scored 50 in the first seven overs but became becalmed against Australia's slow bowlers.

Harris took two wickets in an over with her off-spinners to reduce Sri Lanka to 69 for three as they added only another 19 runs in seven overs.

Schutt took four wickets in her last two overs to prevent a late burst of scoring in the 'death' overs.

Wicketkeeper Healy made three stumpings as the Sri Lankan batters tried to break the shackles.

Healy and Mooney were seldom troubled and scored at well above the required run rate.

Healy frequently used her feet to Sri Lanka's assortment of spin bowlers and hit six fours and a six off 43 balls, while the left-handed Mooney ended a poor start to her tournament with good timing and placement in striking seven boundaries off 53 deliveries.

Mooney was out for nought in a warm-up match against Ireland and made nought and two in her first two innings at the World Cup.

The two teams went into the match tied at the top of Group One after winning their first two games.

Brief scores:

Sri Lanka 112-8 in 20 overs (H. Samarawickrama 34; M. Schutt 4-24, G. Harris 2-7) v Australia 113-0 in 15.5 overs (B. Mooney 56 not out, A. Healy 54 not out)