A constable can search you without a warrant if they think you have committed a crime against sections 78, 78AAA, 78AAB, or 78AA of the Crimes Act 1961. They must believe it is very urgent and they need to act quickly. They also need to think there is evidence somewhere that shows you committed the crime. A constable can search a place, vehicle, or thing if they believe it has evidence of the crime. They must have reasonable grounds to suspect the crime has been, is being, or will be committed. You can read more about these crimes in the Crimes Act 1961, specifically in sections 78, 78AAA, 78AAB, or 78AA. The constable must have good reasons to think the evidence is there and that it is connected to the crime. They can search for things that will be used to commit the crime too. This is all part of the Search and Surveillance Act 2012.