Police officers who deliberately faked their uniform badge numbers to avoid being identified as they weighed into a violent public protest will keep their jobs and won't be investigated by the force's watchdog.

Two of the officers were found guilty of breaching their own code of conduct and a third was said to have a "performance issue" after they were caught using matching identification badges at an Occupy Auckland eviction in January 2012.

Despite the pre-meditation involved, the Independent Police Conduct Authority decided the three officers' behaviour was not serious enough to warrant its attention, saying investigators were too busy dealing with cases involving death and bodily harm.

Rights activists say the disciplinary action is no more than a "slap on the hand" and proves the police regulatory system lacks transparency, accountability and independence.

They believe the police officers were acting in a premeditated way to avoid identification if they chose to lash out in what was, at times, a violent clash between police and protesters.

It is police policy for officers to wear visible, individual numbers so they can be identified by the public if complaints are made against them

"It's extremely serious that these officers can, in a concentrated way, deliberately breach their operating guidelines to avoid the consequences of what they intended to carry out," said veteran activist John Minto.

"If the police take such a cavalier attitude to this, what does that say about their mindset and culture?"

The officers were first spotted with the matching badge number - Z557 - by student Merlin Blackmore at the forced eviction of protesters in Auckland's Aotea Square on January 23, 2012.

At the time of the incident, Police Commissioner Peter Marshall also expressed his disappointment. "I hope it isn't true, but if such stupidity did occur - give me strength," Marshall wrote in his blog on the police website. "Talk about scoring an own goal."

When asked for comment on last week, Marshall said he was "satisfied" the three staff were dealt with appropriately under the police code of conduct.

"While the employment investigation found no malicious intent, their actions fell below the standards of professionalism I would expect," he said.

"I am satisfied the staff involved in this incident are now fully aware of the foolishness of their actions." Marshall was confident it was an isolated case. Both the IPCA and police refused to release details of the investigation, including the officers' motives for wanting to obscure their identities.

The IPCA said that, given its limited resources, it was better for the police to undertake their own investigation.

"Our five investigators have a heavy workload of many cases involving death and serious bodily harm to independently investigate," it said.

The IPCA said if there was any further complaint or expression of dissatisfaction, the authority could choose to investigate further, "but that [was] not likely at this stage".

Blackmore felt the process lacked transparency.

"If police do anything wrong they need to be held to account. It's vital that the public have confidence in them," he said.

"Wearing matching badge numbers is like seeing a hit-and-run and getting the plate number but then having three cars registered with that number."

Auckland Council for Civil Liberties president Barry Wilson said ID badges were integral to the complaints process and often came up in court.

"Quite often protests become controversial, and people who are protesting come into conflict with the police. How can you answer what was right or wrong unless you can ID who the officers involved are?" he said.

Wilson said it was disappointing the IPCA did not accept jurisdiction for a case where officers were potentially combining efforts to defeat the purpose of an inquiry.

The Occupy protesters moved into the square in October 2011 and remained there until the forced eviction in January to voice concern about the concentration of wealth and excesses of capitalism in the wake of the global financial crisis.

Last week, a High Court judge said the Auckland Council, which ordered the eviction, had gone "too far" in removing the protesters.