Police were also appealing for a woman who was given a ride in the area at the time to come forward, Ms Given said.
"A man driving through the Hunua Gorge was waved down by a woman at around 4am on Sunday morning.
"This motorist dropped her at a Valentine Street address in Papakura. We'd like to identify this woman and see if she can assist with our investigation."
The woman was distressed when she was picked up, and stated that she had been drinking, Ms Given said.
She was described as Maori or Polynesian, wearing black tight shorts to her knees and a blue sweatshirt, and had black hair in a ponytail.
"We ask that this woman gets in touch with us as soon as possible," Ms Given said.
"We believe that someone on Valentine Street will know who this is. Anyone who had a woman fitting this description come home on Sunday morning around 4am should let us know."
Anyone with relevant information was asked to contact Counties Manukau Police Serious Crash Unit on 09 262 9109. Alternatively, information can be provided anonymously through Crimestoppers on 0800 555 111.
Victim Support was supporting Mr Strang's family.