Under s 365(1) of the PPRA, 'reasonably necessary' refers to whether the arrest is reasonably necessary, not whether arrest without a warrant is reasonably necessary; the officer need not weigh the relative merits of arrest with versus without a warrant. The assessment of reasonable necessity under s 365(1) does not require the officer to consider the means by which the arrest will be effected, including whether entry into a dwelling will be required, as the power to enter premises is separately governed by s 21. The 12 reasons in s 365(1) serve two functions: authorising warrantless arrest in situations of urgency or necessity, and authorising warrantless arrest for specified offences that have a civil disobedience character.
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