Twitter — yes, twitter! — is yet another great source of legal information.
One recent tweet referred to an appeal against hindering police. It seems that the Law Enforcement (Powers and Responsibilities) Act 2002 (NSW) s 99(3) expressly prohibits police from arresting people unless for one of a several prescribed reasons (similar to s 458(1) in the Victorian Crimes Act).
In DPP v Carr (2002) 127 A Crim R 151;  NSWSC 194 the NSW Supreme Court held a magistrate was correct to conclude the evidence of resisting, assaulting and intimidating police was improperly obtained and subject to exclusion under s 138 of the Evidence Act because it resulted from an arrest for a summary offence of offensive language. (The DPP appeal succeeded on a different point about procedural fairness.)
Crimes Act 1958 s 461(2) provides that police need not arrest a person when a summons or notice to appear will effectively commence proceedings. Children, Youth & Families Act 2005 s 345 sounds like it’s even stronger — children to be proceeded against by summons except in exceptional circumstances — though the section restricts registrars from issuing first-instance arrest warrants, rather than proscribing arrest and charge by police.
Neither of those provisions go as far as the NSW one above, which provides police must-not-arrest-unless-necessary.
But, combined with Charter s 21(2) (freedom from arbitrary arrest or detention), and perhaps also s 12 (freedom of movement), s 13 (right to privacy and reputation), and perhaps s 10 (protection from cruel, inhuman or degrading treatment) and s 25 (presumption of innocence), I think the reasoning in DPP v Carr gains greater significance.
The riposté from prosecutors will probably be Crimes Act s 461 (arrest on reasonable grounds not taken to be unlawful) and cases such as Jensen v Eleftheriou  VR 184.
It remains to be seen which approach will triumph. There haven’t been any resounding wins with application of the Charter of Human Rights and Responsibilities so far — but that could be about to change with the High Court poised to consider its first Charter case soon!