Many shoppers have praised and criticised the move on social media, saying it was either too early or just what they wanted.
On Facebook, one person wrote: "Excuse the f**k out of me Woolworths. It is December god damn 27th! That April fools joke is a little too early."
Another wrote: "Really ... this is just too much!"
Both supermarkets confirmed to News Corp Australia today that not every supermarket was stocking hot cross buns — only those whose bakers have decided to get a head start and bake them early.
A spokeswoman from Woolworths confirmed that hot cross buns will be rolled out nationally across all of their stores from January 2.
Last year alone, Woolworths sold 10 million hot cross buns across Australia in January.
"We know many of our customers love getting delicious hot cross buns as soon as they can and we see high demand immediately when they hit our shelves — with 10 million hot cross buns sold just in January last year," she said.
"Some of our in store bakers have simply been perfecting their wares ahead of the official in store launch next week.
"With Easter earlier this year, we know many of them have been hoping to meet their customers requests to get their favourite hot cross buns back on the shelves.
"We are proud to share that customers can officially look forward to freshly baked hot cross buns in all Woolworths stores nationwide, with a brand new variety this year, from January 2."
However, Coles' national rollout of hot cross buns will occur a day later on January 3.
A spokeswoman said that there will be six different varieties available.
"Hot cross buns are a clear customer favourite so we're excited to offer six delicious varieties across our stores from early January," she said.
"Coles customers can choose from Traditional, made with 100 per cent Australian fruit (regular or mini sized), Fruit Free, Chocolate, Apple and Cinnamon or Gluten Free."