Only the 417 for six against Afghanistan at Perth last year exceeded last night's mark in Australia. New Zealand gave the chase a reasonable run for a time, firstly through Martin Guptill's flying 45 at the start, then Williamson and Jimmy Neesham putting on 125 in 135 balls for the third wicket.
But from the time Neesham, after his highest ODI score, 74, and Colin Munro departed in 16 balls it was effectively over for New Zealand.
Williamson played a classy innings before falling to a Pat Cummins slower ball to be caught at cover.
Australia's bowling wasn't terrific but it didn't need to be - steady and tidy was good enough.
Earlier New Zealand's bowlers felt the pain of an Australian onslaught for the second consecutive game, and this beating was even harder to take than Sydney.
In the opener at Sydney on Sunday, New Zealand were clobbered to the tune of 324 for eight, poor bowling copping serious punishment.
On that occasion, New Zealand had no say as Australian captain Steve Smith won the toss. This time the only reason for Williamson's decision seemed to be the help the seamers might get early from the damp, heavy conditions. It proved an awful clanger.
In the last six games at Manuka Oval since 2013, the team batting first has won the match. In their last three innings on Manuka Oval, Australia totalled 1006 runs for 20 wickets. Evidence enough you might think.
Whatever plans New Zealand had made, and they insisted they had them, were hard to find.
David Warner set about his work effectively and completed his 10th ODI century, and first against New Zealand, in 101 balls.
It was his sixth this year, and only Indians Sachin Tendulkar (nine) and Sourav Ganguly (seven) have made more in a year.
He shared a 145-run stand in 23.5 overs with Smith, who seemed set for back-to-back centuries only to sky a catch to deep cover at 72.
The platform thus laid, lefthander Travis Head pushed a growing case for a test tour to India in February, by smearing 57 off 32 balls, adding 71 in 41 balls with Mitchell Marsh.
And it was Marsh who provided the icing on top, taking three successive sixes off Matt Henry in the 50th over to race to an unbeaten 76 off 40 balls.
It was an ugly day for the bowlers, only one of whom seemed to have much idea how to stem the tide.
The notable exception was left arm spinner Mitchell Santner, who had early success dismissing Aaron Finch and kept a good line to put a decent clamp on batsmen looking to get after him.
It was impressive work under pressure. But he was alone in that.
For a team coach Mike Hesson had praised on Monday as a fine fielding unit, once again it was sub standard for too much of the innings, the ground work ragged as Australian turned on the heat. Bowlers glared at fielders as shots weren't cut off, or pickups were fumbled.
Henry had a shocker, and in two games his combined figures are 20-0-165-2. Only Santner conceded less than six an over. It's the first time New Zealand have had two bowlers - Henry and Trent Boult - concede 80 or more runs in the same ODI innings.
