Officers were called to the Papamoa shops around midday last Thursday.
James Cullen, a staffer at the nearby Flying Mullet Bar, said last Thursday he was alerted to baby in the car after a young girl - aged about 5 years old - approached him looking for her mother.
Cullen said as he walked the little girl over to the TAB, he heard a baby's screams coming from a nearby vehicle.
A few members of the public had also stopped to look into the car, where they could see a baby he guessed was about five months old.
"I don't know how long [the baby] was there for, but he was screaming pretty loud,'' he said.
"We were just trying to hunt down the mother or the father and we found the mother playing pokies in there.''
The temperature high in Tauranga last Thursday was 25C.
The incident came after a number of recent cases where children had been left in hot vehicles as their parents were out shopping.
An Auckland man alerted security staff at the Pak'nSave in Silverdale last week after spotting a toddler in a locked vehicle.
Last Monday, a woman shopping in Napier found a child distressed and sweating profusely, still locked into their car seat, after being left in a locked hot car in 33C heat while their mother was inside shopping.