Austrian laws forsees provisions for the optical and acoustic surveillance of persons.
The optical and acoustic surveillance of persons is admissible
1. if and for as long as it is urgently suspected that a person affected by the surveillance has kidnapped or otherwise seized another person, and if the surveillance is restricted to processes and comments at the time and location of the deprivation of liberty,
2. if it is restricted to processes and comments that are intended to be brought to the knowledge of an under-cover investigator, or another person informed of the surveillance, or that may be perceived by that person directly, and if it appears to be required in order to clear up a punishable offence carrying a prison term of more than three years, or
3. if the clearing up of a crime carrying a prison term of more than ten years, or of a crime by a criminal organization or terrorist association (§ 278a and § 278b of the Criminal Code), or the clearing up or prevention of a punishable act committed or planned within the framework of such an organization or association, or the determination of the whereabouts of the person accused of such a punishable act would otherwise be without prospects of success or be essentially impeded, and
a. the person who is the target of the surveillance is urgently suspected of a crime carrying a prison term of more than ten years, or of a crime pursuant to § 278 a or § 278b of the Criminal Code, or
b. it is to be expected, on account of certain facts, that a person who is thus urgently suspected will establish contact with the person who is the target of the surveillance.
To the extent that this is unavoidable for performing the surveillance pursuant to paragraph (1) item 3, it shall be admissible to penetrate a certain flat or other rooms protected by domestic authority, if it is to be expected, on account of certain facts, that the accused will use the rooms in question.
The optical surveillance of persons in the process of clearing up a punishable act is also admissible
1. if it is restricted to processes outside of a flat or other rooms protected by domestic authority, and if it is conducted exclusively for the purpose of monitoring objects or premises in order to record the conduct of persons who enter into contact with the objects, or who enter the premises, or
2. if it is performed exclusively for the purpose mentioned in item 1 in a flat or other rooms protected by domestic authority, and the clearing up of a punishable act, committed with intent, that carries a prison term of more than one year, would otherwise be essentially impeded, and the proprietor of that flat or those rooms expressly agrees to the surveillance.