Northern Territory Police have arrested three more people in connection with the murder of a man near Alice Springs last week.

Police allege a group of five men travelled to the New Iparpa town camp south of the Red Centre town last Monday night to find a 33-year-old man.

He was driven to Charles Creek, north of the town, and assaulted.

Detective Sergeant Tony Henrys alleges that what followed was a prolonged attack, with the victim being clubbed with steel bars and tree branches, and stabbed numerous times.

He says that, so far, six people are in custody and five of them have been charged with murder.

Police are calling for witnesses to come forward.

"We are particularly looking for a tourist who called triple-O on Monday night, just before midnight," he said.