The majority in Rongonui v R  NZSC 92 did not share the Chief Justice's view that "res gestae" is an outmoded term (see Hart v R  NZSC 91 at 17, noted below).
In Rongonui, Blanchard, Tipping, McGrath and Wilson JJ held jointly that res gestae statements are not within the scope of s 35 Evidence Act 2006 (prior consistent statements) . Terminology might be in doubt, as the judgment refers to "what used to be called" res gestae evidence , and at  the phrase "words spoken in the course of the events in issue" is used – but that could hardly have been intended to be a convenient substitute for the term "res gestae".
Res gestae statements therefore continue to be admissible in the same circumstances in which they were admissible at common law.
The joint judgment in Rongonui also tidied up what was becoming a needlessly contentious issue: a spurious exclusion of implied statements from the scope of "statements" (see the definition of "statement" in s 4 Evidence Act 2006), especially in relation to the statutory hearsay rule. A statement is an assertion, and an assertion may be express or implied . The Crown in Rongonui could not argue that evidence that the complainant told someone "what had happened" was not an assertion that she had given the same account of events as she was giving in court. Those words carried the implication of consistency, and were accordingly an assertion of consistency, and in the circumstances of this case were an inadmissible prior consistent statement.
There is much overlap between Rongonui and the Court's other decision of today, Hart (see below), especially on the incorporation of what used to be called recent complaint evidence in sex cases into s 35 so that they no longer need to be "recent" in the common law sense, they are admissible as proof of the truth of their assertions, but they are only admissible when the conditions in s 35 are met. That is not a formidable obstacle, as usually the defence in such cases will be alleging recent invention.
It seems to me that if the defence specifies when it claims invention first occurred, consistent statements before that will have a relevance that is more likely to be obvious than consistent statements made after that date, although generalisation is dangerous and the circumstances of each case will need consideration in assessing the probative value of the challenged consistent statement. That there will be difficulties is signaled by the Chief Justice's dissent in Rongonui on the s 35 point.
Barlien got a drubbing today. It has up to now been cited by the Court of Appeal mainly for the point on which it was approved: that when the prior consistent statement is admissible it is admissible as proof of what it asserts. In two cases Barlien has been noted uncritically on other points now corrected by the Supreme Court: in Ringi v R  NZCA 293 it was mentioned as showing the difficulties of s 35, and in a case which carried a suppression order so I only cite its number, CA529/2008, Barlien was mentioned as authority for the proposition that res gestae evidence is no longer admissible. Another aspect of Barlien - observations on potential difficulties concerning identification evidence - has been called into question by the Chief Justice in footnote 29 of Hart; the Court of Appeal cited Barlien uncritically on that point in CA108/2009.
All judges in Rongonui agreed that the trial had involved breaches of s 90(5) Evidence Act 2006, and the joint judgment, with which Elias CJ agreed, contains some comments on deciding when a record is capable of refreshing a witness's memory.