He said on Wednesday papers to this end would be filed at the Western Cape High Court.

The minister said that despite numerous and protracted interactions with Western Cape premier Helen Zille, she had set up the commission and limited its scope.

"The rationale behind the setting up of such a commission; which at a strategic level only focuses on the SA Police Service (SAPS) and not the Western Cape metro police, is suspicious, if not questionable.

"It is evident that she is determined to continue with the commission by hook or crook, which leaves us with no option but to challenge the matter, through the legal framework."

The papers were expected to be filed by Friday.

Earlier in August, Zille appointed a commission of inquiry, headed by retired judge Catherine O'Regan and advocate Vusi Pikoli, citing a breakdown of trust between Khayelitsha residents and the police.

It planned to hold public hearings between November 12 and December 14, and submit a full report by February 24 next year.

Mthethwa said he had outlined substantive reasons to Zille as to why the establishment of the commission was premature.

His spokesman Zweli Mnisi elaborated that a holistic view had to be taken when looking at crime and crime-fighting in communities. One had to look beyond the police towards the criminal justice system and unique social challenges.

"It's a value chain," Mnisi said.

"For one, there is a lack of understanding of the criminal justice system. Police are often accused of giving suspects free bail when they don't even deal with these issues."

The community's response to criminals was crucial.

In some cases, they phoned the media before police. In other cases, they chose not to report known criminals for their own reasons.

When looking at how the police responded to crime, there was a "mixed bag" of situations, factors and challenges, Mnisi said.

The minister's approach was to continuously evaluate and improve stations and officers.

"When it comes to training, nobody can stand on a rooftop and say I'm an expert," Mnisi said.

The commission said on Wednesday it had to decided to forge ahead with its work despite threats of legal action.

On Tuesday, it served subpoenas on provincial police commissioner Arno Lamoer and the station commanders of Khayelitsha, Lingelethu and Harare police stations.

A subpoena was also issued last Friday on Lamla Tyhalisisu, the acting provincial head of the Independent Police Investigative Directorate (Ipid).

He accepted the subpoena on behalf of head Thabo Leholo, who was out of the office at the time.

According to evidence leader advocate Nazreen Bawa, the subpoenas requested the police to be present and give evidence on November 12, and produce specified books, documents or objects in their possession or under their control.

"These include details of staff working at the three police stations between the period January 1, 2010 to August 31, 2012; documents reflecting complaints lodged and received from the Ipid and its predecessor, the Independent Complaints Directorate; minutes and documents relating to community police forums; crime statistics; information relating to dockets under the investigation of the police; as well as information relating to the investigation of vigilante violence and killings in Khayelitsha."

Zille's spokesman Zak Mbhele said the premier would not comment on the matter until an interdict had been served, referring all queries to the commission.