"He does not look like a friendly robot from any angle!" one wrote.
"Those blue angular lights are like nasty squinting eyes silently judging you."
Another agreed, saying it seems "creepy and useless".
Others questioned whether the robot was taking human jobs. However, it is expected that "Greggles" will share the role with existing cleaning staff.
Shoppers in favour of the automation praised Woolworths for trying something new.
"I love it, I was very impressed with Greggles," one said.
Another wrote: "Staff can’t always be there so to have Greggles is a huge help."
A Woolworths spokesperson tells New Idea Food: "We’ve been working hard to reduce trips and slips in our stores, but we still see too many.
"We’re trialling new technology in this store to see if it can help make the store safer for our customers and team.
"It will roam the store and scan the floor for any potential safety hazards, which our team can then respond to.
"It’s exciting technology for us to trial, but we’ll be very mindful of customer and team member feedback on it. We have no plans to rollout the technology any further at this time."