Another motorist said the man was on the left-hand side of the road closer to Mill Rd with his arm out towards Takanini.
"I saw a glimpse of his red-checkered shirt. He was hidden in the dark till you got a bit closer," the motorists said.
"He didn't look around or anything, just head down while walking and arm was up."
Emergency services were first called at 7.20pm last night after reports said a pedestrian had been hit by a car on Popes Rd.
"On arrival, Police found a man deceased," a police spokesperson said.
"Initial indications are that the man was already deceased on the road when hit by the driver who contacted emergency services.
"We would, however, like to hear from anyone who saw a man wearing a red-checked shirt and jeans hitchhiking along Popes Rd".
Police will not release any further details into the incident as there are still family members to be notified of his death.
A spokesperson said they would like to speak to anyone who may have seen the man hitchhiking in the area around 7pm and 7.30pm yesterday.
"Anyone with information that can assist our inquiries is asked to call Counties Manukau Crime Squad on 09 261 1321."