Glenn Maxwell's unbeaten 54 helped Australia beat Afghanistan by four runs to stay in the hunt for the semi-finals at the Twenty20 World Cup on Friday in Adelaide.

The result ensured New Zealand book their final-four spot from Group 1. The hosts and defending champions Australia need England to lose their final Super 12 match on Saturday against Sri Lanka to make the last four.

Glenn Maxwell hit an unbeaten 54 in the face of some inspired Afghan bowling to steer Australia to 168-8 in their must-win Twenty20 World Cup clash.

The defending champions and hosts need to win, and handsomely, in Adelaide to boost their net run rate for a place in the semi-finals.

Earlier, New Zealand all but booked their final-four spot from the same group with a comfortable 35-run win over Ireland in the first match of the day at the Adelaide Oval.

Australia lost skipper Aaron Finch and Tim David to hamstring injuries and dropped pace bowler Mitchell Starc before being invited to bat first.

Australia kept losing wickets but Maxwell stood firm in his 32-ball knock studded with six fours and two sixes to hand his team a badly needed competitive total.

Naveen-ul-Haq rocked Australia's top order with the wickets of David Warner, for 28, and the returning Steve Smith, for four, in one over. He returned impressive figures of 3-21.

The left-handed Warner came out firing to smash spinner Mujeeb Ur Rahman for three straight boundaries in the second over of the match.

He lost fellow opener Cameron Green off Fazalhaq Farooqi, who took two wickets, in the next over but kept up the attack with Mitchell Marsh, who hit 45 off 30 balls.

Naveen bowled Warner and four balls later the fast bowler trapped Smith lbw.

Marsh attempted to hit back with a six and two fours off Gulbadin Naib but failed to build on it and he fell caught behind to Mujeeb's mystery spin.

Maxwell and Marcus Stoinis, who hit Australia's fastest T20 50 -- in 17 balls -- in the win over Sri Lanka in Perth, then got going against the Afghan bowlers, only for Rashid Khan to break through.

Stoinis smashed Rashid for a six over mid-wicket but soon departed for 25 as Afghanistan kept chipping away.