Perry (68 off 86) and McGrath (57 off 56) hit fine half-centuries before Gardner played a 18-ball 48-run cameo to help Australia post a challenging 269 for eight after being asked to bat.
Defending the target, Australia dished out a cohesive bowling effort to bowl out trans-tasman rivals New Zealand for 128 in 30.2 overs.
Darcie Brown (3/22) was the pick of the bowlers for Australia while Amanda-Jade Wellington (2/34), Gardner (2/15), Perry (1/18), McGrath (1/17) and Megan Schutt (1/22) provided the perfect support from the other end.
Three wins in three matches for Australia 🔥#CWC22 https://t.co/iCDZAGZnNz
— ICC Cricket World Cup (@cricketworldcup) 1647145435000
With three wins from as many matches, Australia displaced India from the top of the eight-team standings with six points.
Sent into bat, the opening pair of Rachel Haynes (30) and Alyssa Healy (15) shared 37 runs in 9.5 overs as Australia made a sedate start.
Australia were dealt twin blows soon when skipper Meg Lanning (5) and Healy departed in quick succession.
Perry and Beth Mooney (30) then stabilised the innings with a 57-run fourth-wicket stand before the latter perished.
Australia pull off a comprehensive 141-run win over New Zealand thanks to some big hitting with the bat and a remar… https://t.co/tYIecthVgZ
— ICC Cricket World Cup (@cricketworldcup) 1647144545000
Perry was then joined by McGrath as the duo took the attack to the opposition to stitch 90 runs off 84 balls to take Australia past the 200-run mark before both the batters were dismissed in quick time.
While Perry struck six boundaries and one six during her stay, McGrath’s innings was laced with eight hits to the fence.
The final push was provided by Gardner who used her long handle to great effect, hitting four boundaries and as many sixes to take Australia past the 250-run mark.
Lea Tahuhu (3/53) picked up three wickets for New Zealand.
The Australian bowlers were right on the money while defending the target, picking up wickets at regular intervals which unsettled New Zealand.
New Zealand’s chase never got going as they lost wickets in a heap from the word go and failed to counter Australia’s incisive bowling effort.
Amy Satterthwaite was the top-scorer for New Zealand with 44 off 67 balls and the second best score was from tail-ender Tahuhu who made 23 off 25 balls.
Katey Martin (19) and opener Suzie Bates (16) were the two other batters who managed double digit scores as New Zealand failed to put any sort of challenge.
Australia: 269 for 8 in 50 overs (Ellyse Perry 68, Tahila McGrath 57, Ashleigh Gardner 48; Lea Tahuhu 3/53).
New Zealand: 128 all out in 30.2 overs (Amy Satterthwaite 44; Darcie Brown 3/22, Ashleigh Gardner 2/15, Amanda-Jade Wellington 2/34).