"It was a bit of a shock," Mr Collins said.
There was a birthing clinic 300m down the road but the woman was unable to make it that far.
Mr Collins then called an ambulance and his patrol partner drove to the clinic for a midwife.
"She kept saying, 'The baby's coming, the baby's coming'," he said.
The healthy boy was soon delivered - with the help of his father and Mr Collins.
"Dad had his hands ready for the baby and I had my hands under his hands just in case.
"The baby came out into dad's hands and couple of seconds later, I heard that nice cry - it was probably the best sounds you've ever heard," he said.
Mr Collins praised both parents.
"She was breathing well. She was so brave. Dad was proud as punch."
Mr Collins wasn't a complete newbie when it came to helping with a birth.
"I've seen my wife give birth before, but it's very different when you've got all that support around you."
But for this roadside birth, there was only the mother and the father, he said.
Mr Collins said he had heard about other police officers helping with births, but "you never really think it would happen to you".
"It was the most memorable job. It was nice to be a part of it."
He said a few other officers arrived on scene to block the street so the woman could have privacy.
After giving birth, the mother was transferred to the birthing clinic in an ambulance.
Mr Collins has yet to get in touch with the proud parents, but said he would like to send them a gift.
The birthing practice will come in handy for Mr Collins -- he and his wife are expecting their second child soon.
