The family of slain liquor store co-owner Navtej Singh are to complain about the police handling of his shooting, saying they are doing it for the community.

Family representatives and the New Zealand Sikh Society deciddd to lodge a formal complaint with the Independent Police Conduct Authority at a meeting last night.

The Sikh community had raised concerns over the length of time it took for Mr Singh to get medical treatment after he was shot at his Manurewa liquor store on June 7.

The first 111 call about the robbery was received about 9.05am 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.

Mr Singh, shot in the chest, died in Middlemore Hospital the next morning.

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)," he told NZPA.

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.

"If the community are doing something for the family and for the community then we should be proud of that."

Sikh Society spokesman Daljit Singh said the complaint was being made 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," he told NZPA.

"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 at 2pm on Saturday in Manukau.

Two men were charged with Mr Singh's murder, aggravated robbery and armed robbery charges last week. They will appear at a pre-depositions hearing in August. Two other men have been charged with armed robbery.