The New Zealand Sikh Society and the family of slain liquor store co-owner Navtej Singh are to make a formal complaint about the police handling of the case.
The complaint will focus on the police decision to hold back an ambulance from reaching the Manurewa store in south Auckland despite several calls from family and friends saying the gunmen had left the scene.
Mr Singh, 30, died in Middlemore Hospital 24 hours after being shot while apparently offering no resistance to three armed robbers at the Riverton Liquor Store in the Randwick Park area of Manurewa on June 7.
The first 111 call following the beginning of the robbery was received about 9.05pm but police did not enter the store until 9.31pm and paramedics entered at 9.38pm - 20 minutes after they arrived at a "safe point" near the scene.
Police later said they had to establish where the gunmen were before they entered the scene so nobody else's life was at risk.
At a meeting of about 15 community leaders last night it was decided to lodge a formal complaint with the Independent Police Conduct Authority.
New Zealand Sikh Society spokesman Daljit Singh said the complaint was not being made for financial gain but to ensure no one else was put in the same situation.
"Every person should have that right that if he, or she, needs medical help it should arrive immediately.
"The family was sitting in the meeting ... actually it was their decision [to make the complaint] and the New Zealand Sikh Society took the matter from them and said okay, we are ready to support you if you want to do that."
Mr Singh said a rally against crime would also be held on Saturday afternoon in Manukau.
Sandeep Verma, spokesman for the victim's family, said the Sikh Society was helping the family to get justice.
"There are still some unanswered questions from the police and the other authorities about why Navtej Singh didn't get the treatment when he was shot.
"He might have survived ... if he had got the treatment [earlier]."
Mr Verma said the family didn't know what the outcome of the complaint would be, but hoped it would bring about change that was "helpful to the community".
* Two men were charged with Mr Singh's murder, aggravated robbery and armed robbery charges last week. Two other men have been charged with armed robbery.