Mum Selina who posted her complaint on the Morrisons Facebook page
Morrisons confirmed the incident had taken place after Selina Johnson posted a message on Facebook saying her boy had 'cried his heart out'.
The incident happened in the Chorley, Lancashire, branch of the supermarket on Wednesday lunchtime, resulting in police being called.
According to the Mail, Selina's Facebook message said: "Today I had the worst experience any parent could have, today one of your staff smacked my four-year-old's legs.
"My poor little boy cried his heart out. I have complained to the store manager and called the police who will be taking a statement and we will be pressing charges.
"I will never set foot in on one of your stores again."
The message was posted publicly to Morrisons, which has more than 300,000 fans on Facebook.
A spokesman for Morrisons said: "The member of staff in question has been suspended pending a disciplinary next week."
However, he said discussions had taken place with 'all parties', and police would not be pressing charges.
A Lancashire Police spokesman said: "It was reported to us but it was settled by community resolution.
"We spoke to all parties involved and everybody was happy with the outcome.
"The member of staff was spoken to and said she tapped a child in a friendly manner but realised afterwards this may have been misjudged.
"The family were more than happy with the outcome so there's been no formal action on our part."
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