"To all the mothers and mother figures out there, a huge thank you. I count myself lucky every day to have the best you could ever imagine.
Ardern's message pulled many mothers' heartstrings across New Zealand as they thanked her for looking after the country.
"You have also taken care of us and the country just like a mother ... a big thanks to you," one person wrote.
Another added: "Happy Mother's day PM! Your mum has produced and raised an amazing, smart, kind, graceful and awesome role model that my girls and I look up to ... you are special ... give your mum an extra special hug she deserves it and we thank her.
While another wrote: "Happy Mother's Day to you both. Hopefully we can get through these crazy times and can get back to seeing our mums who are far away. Thanks for your leadership to get us through these times so we still have our mothers even if we can't see them on Mother's Day."
The post comes after a group of f famous Kiwi mums made a "quarantine style" video together, passing each other a virtual chocolate bar and wishing everyone a Happy Mother's Day.
Urzila Carlson, Lucy Lawless, Irene van Dyk, Hilary Barry and Jacinda Ardern got together, while apart, to celebrate Mother's Day within their "coffee group".
They each shared a kind message before "passing" on a block of chocolate to one another.