Barden Ridge mother Liz Peek delivers baby Elijah under super moon on side of Bangor Bypass

Liz and Jeremy Peek were driving to Sutherland Hospital in Sydney's southern suburbs before dawn when their third child, Elijah William, decided he could wait no longer.

They pulled over about 150 metres into the Bangor Bypass, where Ms Peek gave birth - with her husband's help.

"It was relatively private," she said. "We had the noise wall on one side and trees around us.

"It was the last night of the super moon, there was a light mist in the air and the sky was clear and the stars bright.

"It was magic - a calm, intimate, most powerful experience, and then straight after you are on an enormous high."

Police and paramedics arrived soon after and the couple completed their shared experience in an ambulance, where Mr Peek cut the baby's umbilical cord.

They were taken by ambulance to hospital and, after getting the all-clear, were back home with their daughters Evelyn, 3, and Penelope, 1, before lunch.

Adding to the feeling there was something very special about this birth was that Elijah arrived in the world at 5.25am on June 25 and brought such joy to the first responders and the COVID-weary, wider community.

"Everyone was so happy by the roadside," Mr Peek said. "They were doing high-fives and saying things like, 'It's been a tough day, but this makes it so great'."

Mr Peek said in a Facebook post: "We birthed our little man this morning under the last super moon of 2021 - the strawberry moon, under the stars, in the crisp winter air. The two of us soon become the three of us on the Cnr of Old Illawarra Rd & the Bangor Bypass.

"Police arrived soon afterwards ... they promptly closed 2 of 3 lanes for us despite the birth being well and truly over. Following came the paramedics, providing us a means to cut the cord, have a natural third stage and take us to hospital for all the mandatory checks. We were thrilled to have our community's first responders sharing in the excitement of Elijah's arrival."

In a following post, Mr Peek said: "Eli's life in 60 hours has so far consisted of meeting 6 police officers, 4 paramedics, 2 midwives, the grandparents, uncle spud, surviving his fawning sisters, first interview with the press and had his first 24 hours of a COVID lockdown.

"Wouldn't expect anything less fast paced from the Road Warrior born on the Fury Road (Bypass) under the last super moon of 2021."