If you are arrested certain things apply and the police must comply with Police General Orders and departmental rules when they interview you. In most cases:

An interrogation can proceed if the offence is not serious and it is not practicable to contact a relative or friend. You do not have to answer questions unless you wish.

Note: The right to a phone call or for a friend to be present, might be denied in some circumstances, e.g. if your friend is involved in the alleged offence.

The police have the power to search you, take your photograph and your fingerprints. In certain circumstances they can arrange for body samples to be taken from you. Police can take anything found on you and may use such force as is reasonably necessary for those purposes. Police cannot put a spit hood on you, and it is a criminal offence if they try to do so. In certain circumstances the police can have you examined by a doctor but you have the right to have a doctor of your own choice also examine you.

[Police General Orders 1320 18:1, 18:6, 20:1, 20:3, 3065, 8:1, 9:5]

[Summary Offences Act 1953 (SA) ss 79A , 81, 82A]

See: Arrest, Your Rights, and Bail