Eight of the surveillance warrants detailed by police in its 2018-19 Surveillance Devices annual report were issued for the suspected offence of "participating in a criminal group - causing harm, contrary to section 653 of the Criminal Code 2002 (ACT)", together with the additional suspected offence of attempted murder.

However, only one of the bikie phonetap warrants yielded information of use to police investigations. Three were deemed to be of "limited use" and four were not even activated.

Taskforce Nemesis ramped up its activities late last year when Canberra was racked by a factional bikie war resulting from members of the Comancheros outlaw motorcycle gang patching over to a rival gang, the Finks.

The dispute spilled over into suburbs with a group of armed men jumping the backyard of a Calwell house, torching three cars in the garage and firing guns at a man inside the house. The man inside returned fire with a rifle and lost a finger in the shootout.

The ACT also became a focus of bikie turf wars as gangs sought to escape the restrictions imposed on them in NSW and Queensland through anti-consorting laws, and set up chapters in Canberra.

ACT police sought and obtained 137 warrants for surveillance during the reporting year, almost four times the number obtained in 2017-18.

These resulted in eight arrests and just one conviction, although some of the cases are still pending.

Aside from the bikie cases, seven people were placed under surveillance for suspected cocaine or MDMA trafficking, seven in relation to a murder investigation, and 12 in relation to aggravated robbery offences.

The records reveal that during 2018-19, ACT police were granted warrants to spy on 36 people's data records, record 37 people's conversations, track 29 people and visually monitor 35 people.

However, the warrant numbers do not provide a true indication of how many people were under suspicion because of the changing nature of eavesdropping, tracking and recording technology.

In 26 of these cases, the warrants were for multiple surveillance functions - data searching, audio recording, optical and location tracking - and focused on one device, usually a suspect's smartphone.

Under the act, all surveillance device warrants must be issued by judges appointed to the ACT Supreme Court but police are required by law to apply for each of the surveillance functions separately, even if they apply to a single device or IP address.

The newest interception and hacking capabilities used by police are a hyper-extension of the way that app-trackers and data-gatherers already harvest your personal information to better target you for advertising.

A mobile telephone capable of making an audio recording is a "listening device" for the purposes of the Surveillance Devices Act and with a warrant, police can track location and movement, record all the numbers called, SMS messages exchanged, track all internet browsing, read emails and monitor social media use and contacts.

If the suspect also inadvertently accepts malware from a third party - which can be disguised in packets of apparently innocuous data - then the camera and microphone can activated remotely.

Some criminal suspects even make it easy for police by allowing their phone apps, such as Google Maps, to be automatically refreshed.

The ACT Ombudsman's Office, which inspects ACT police surveillance records on an intermittent basis, found several administrative breaches by police during 2018-19.

In one breach, police used a warrant signed off by a member of the Administrative Appeals Tribunal. There were also three instances where the kinds of surveillance device authorised on the warrant differed as to what was on the original application.

Under the legislation, if a device is no longer needed to gather evidence in a case then the Chief Police Officer, or a representative, must apply for a revocation.

The Ombudsman reported that twice during the latest financial year, police "had not considered" the requirement and the warrant stayed in use.