It was not yet clear what other charges relating to Mr Samuels' death might follow as the investigation progressed.
Both Mr Samuels and the 44-year-old had been drinking at the 123 Casino Karaoke Bar on Friday night. Mr Samuels had been out with family members, celebrating his wife Alaina's birthday.
CCTV footage from inside the bar did not appear to show any problem between the men inside, bar staff have said.
Members of Mr Samuels' family have said the 44-year-old drove his car into theirs. When Mr Samuels got out to question what was going on he was run down, they said.
Watch: Auckland death: Police investigating
Police have confirmed the two cars came together before the father-of-three was run down.
"There's certainly been a crash between the two vehicles. That forms part of the investigation," Mr Alexander said. "One car has reversed into the side of another."
Mr Samuels' family did not want to talk about the incident yesterday, as they prepare for his funeral in Northland tomorrow.
But members of the Howick Hornets Rugby League club, where the 41-year-old helped manage his children's teams, have spoken of his character.
Matt Hughes, who coached the Under-16/17 team, of which son Dominic Samuels was a member, said Mr Samuels was a mentor to many of the players.
"We've got a team of 17 that were basically a family at the end of the season. And they're all coming up to the funeral this week. It's hit the whole team hard.
"He was just a positive, enthusiastic and caring man ... He was always smiling and always had something positive to say."
First and foremost, Mr Hughes said, he was a proud dad to children Rosalie, Dominic and Rueben.
"The one thing I hope his kids remember is that he was so proud of them. He was a brilliant dad."
Club secretary Darnelle Penu said Mr Samuels' loss would be felt by the club.
"He's going to be a well-missed father of the club."