Ricky Ponting finished stranded on 98 not out off 55 balls after helping Australia recover from 54 for four to pile on 214-5 from their 20 overs.
New Zealand were bowled out for 170 on the last ball of the match despite 66 from Scott Styris and 36 from Brendon McCullum. Australian paceman Michael Kasprowicz was the best of the bowlers, capturing 4-29 from his four overs.
Thursday's match was the world's first 20-over international amid speculation that the abbreviated form of the game could become a regular part of the international calendar.
Scorecard:
Australia
A.Gilchrist c McMillan b Mills 1
M.Clarke c McMillan b Tuffey 7
A.Symonds c McCullum b Mills 32
R.Ponting not out 98
D.Martyn b Mills 3
S.Katich b Cairns 30
M.Hussey not out 31
Extras (lb-9 w-3) 12
Total (for five wickets, 20 overs) 214
Did not bat:
Fall of wickets: 1-10 2-21 3-46 4-54 5-137
Bowling: Tuffey 4-0-50-1 (w-1), Mills 4-0-44-3 (w-2), Cairns 4-0-28-1, Wilson 4-0-43-0, Adams 4-0-40-0
New Zealand innings
B.McCullum c Ponting b Kasprowicz 36
S.Fleming b Kasprowicz 18
M.Sinclair c Katich b Kasprowicz 0
S.Styris b Lee 66
C.McMillan c Hussey b Hopes 9
C.Cairns c McGrath b Kasprowicz 1
H.Marshall b Symonds 8
A.Adams run out 7
J.Wilson b McGrath 18
K.Mills c Kasprowicz b McGrath 0
D.Tuffey not out 5
Extras (w-2) 2
Total (all out, 20 overs) 170
Fall of wickets: 1-49 2-49 3-67 4-93 5-95 6-105 7-121 8-161 9-165 10-170
Bowling: Lee 4-0-26-1 (w-1), McGrath 4-0-48-2, Kasprowicz 4-0-29-4 (w-1), Hopes 3-0-23-1, Symonds 3-0-33-1, Clarke 2-0-11-0
Result: Australia won by 44 runs