England had a defendable total thanks to a 71 run partnership between wicket keeper Paul Nixon (42 not out) and Liam Plunkett (29 not out) after they were on the ropes at 138 for seven.
That defence had a sensational start with three quick wickets.
James Anderson, doubtful for the match with a fractured finger, struck with the sixth ball when Lou Vincent fell for nought after edging to Nixon.
New batsman Ross Taylor then exited for a first ball duck, a nicked drive off Plunkett brilliantly caught one-handed by a diving Andrew Flintoff at first slip.
Black Caps captain Stephen Fleming at least managed seven before a miscued pull off Anderson was well-held by Ed Joyce, running round from square leg.
From 19 for three Styris, who'd earlier taken two for 25, counter-attacked alongside the experienced Craig McMillan.
Their stand was worth 53 until the introduction of Monty Panesar had immediate effect, when he tempted McMillan on his second ball and the Kiwi lofting to Jamie Dalrymple to return to the stands with 27.
Styris continued on and brought up his 50 off 70 balls with his sixth four.
England's lack of runs was adding increased pressure on the field and it showed when Kevin Pietersen dropped Styris on 61 when he had driven Monty Panesar to short cover.
Oram was playing with a lot more patience than he is reputed for but he still brought up his 50 in 68 balls.
Earlier Pietersen had top scored for England with 60.
From 133 for three, England collapsed to lose four wickets for five runs, three going down for one run in seven balls as key batsmen Paul Collingwood (31), Pietersen and Flintoff, out for a first ball nought, all fell in quick succession.
Fast bowler Shane Bond took two wickets in four balls as Pietersen holed out to James Franklin at long-on before Flintoff chipped to Styris at short cover.
Man of the match Styris had started the slump when he removed Collingwood after an attempted guide to third man was well-held by wicket keeper Brendon McCullum to end a fourth-wicket stand of 81, the best of England's innings.
England play Canada on Sunday while New Zealand face Kenya, seven-wicket winners over the North Americans, on Tuesday.