The assault, on April 12, 2017, ended four days of gang-linked skirmishing, which started with another brawl and also involved two separate kidnapping attempts.

The altercations are described in confidential case files obtained by Fairfax Media, revealing the true scale of bikie-related crime in the capital and the extensive police effort to combat it.

ACT Policing investigated 30 bikie-linked incidents between November, 2016 and May last year, according to case summaries released under freedom of information laws.

The Comanchero, Rebels, Nomads and Finks gangs are named in the documents, which detail nine active police investigations into outlaw motorcycle gangs and their involvement in criminal activity.

ACT Policing's criminal investigations boss, Superintendent Scott Moller, said the increase in bikie activity flared-up in 2015.

"Since 2015 there has been a continued increase in serious criminal activity known to be associated with outlaw motor cycle gangs including home invasions, assaults, arsons, kidnapping, extortion, drive-by shootings and other offences involving firearms," he said.

"ACT Policing has also seen an increase in the number of known overt outlaw motorcycle gang runs into, and meetings held, in Canberra involving interstate gang members since 2015."

The case files stretch back to November 14 last year, when three balaclava-clad intruders burst into a Crace home during an aggravated burglary.

"Three persons of interest have attended the location with baseball bats [and a] gun and assaulted housemate and took friend's car keys," read the police files.

"Came in through the back…complainant opened the door then they pulled out the weapons."

Two days later a suspected shooting in Calwell was also linked to gang activity.

"Complainant states he awoke to the glass breaking at the front door, looks like a bullet hole into the glass then into the wall," officers wrote.

"Police observed a hole through a pane of glass and approximately 17 impact marks in the wooden sections of the door."

The simmering feud between the Nomad and Comanchero gangs boiled over in July this year with a series of high-profile shootings and arson attacks.

But the recently-released files also detailed the police force's battle to keep on top of a constant undercurrent of gang activity taking place away from the public eye.

"ACT Policing could always do more with additional resources," Superintendent Moller said.

"However, ACT Policing is adequately resourced to disrupt and dismantle the illegal activities of criminal gangs in the ACT.

"The ACT Policing response to criminal gangs is a key priority, and is supported by the entire organisation."

Police have struck back with a number of arrests in recent months.

Among them, Owen Turnbull, an alleged senior Nomad who denies he is still involved with the gang, has pleaded not guilty to drugs charges after police swooped on his Ellerston Avenue home in September.

The home had been targeted twice in drive-by shootings in March and July.

Aaron James Graham, who is also allegedly involved with the Nomads, was charged with weapons offences earlier this month after police seized a cache of guns at a Richardson home.

Two of the firearms found at that house were believed to be similar to those used to pepper a Waramanga house with bullets in July, police said at Mr Graham's hearing.

The files also documented a spike in gang crime throughout April, with an assault, two attempted kidnappings, and a 10-man bashing reported in the space of just four days between April 9 and April 12.

The April violence culminated in the Burns Club assault, in which 10 Comanchero bikies set-upon a sole member of the rival Nomads gang.

"Management of the club advised that offenders had left prior to police arrival, and that they suspected it was a 'bikie-related' fight," police case summaries read.

"They stated the victim of the assault had been taken outside by up to 10 'Islander' males and assaulted."

The Finks gang, who do not have a Canberra clubhouse but are active in regional NSW, were named in the files after members were refused entry to a Civic pub in November.

"Multiple other incidents with Finks OMCG members attempting to enter licensed premises in Canberra city over this weekend," police noted in their report.

Other incidents included a man being slashed with a machete during a three-man robbery in March, and a public five-on-one bashing in Fyshwick on November 25.

"[Redacted] stated at about 5.45pm they were informed a fight was occurring outside," read the police report of the November incident.

"They went outside and saw five males...punching and kicking a Caucasian male. They stated the male was being kicked and punched repeatedly, though he did not fight back."

One witness to the November assault told police they believed the Nomads gang was involved.

Aggravated robberies, burglaries, weapons charges and blackmail are also mentioned in the police case summaries.

One heavily redacted report mentions an incident last December, in which a burning car was rammed into a building.

ACT Labor recently introduced a bill into the ACT legislative assembly aimed at curbing bikie violence in Canberra.

The bill gives police the power to declare a crime scene on private property without a warrant if its occupants refuse to cooperate, and also makes it a crime to shoot at a building, even if it is empty.

Assistant Commissioner Justine Saunders, the ACT's chief police officer, said the force would support any legislation that made it easier to target criminal activity.

"ACT Policing welcomed the recent introduction of legislation which will provide necessary powers to secure crime scenes, in addition to a new offence specifically addressing the increased threat of drive-by shootings," she said.

"ACT Policing is keen to continue working with the ACT government to develop proactive and preventative legislation that will assist police in targeting and stopping the illegal activities of criminal gangs before they occur."