Australian National University demographer Liz Allen said hitting the 27 million population milestone was a moment to consider the challenges and opportunities facing the country in the future.
Dr Allen said it could affect social cohesion and potentially drive harmful rhetoric around migration when Australia's population change was problematised.
"If Australia didn't have immigration, we would not have the socio economic good standing that we have. Immigration keeps Australia economically and socially afloat," she said.