National supermarket chain Woolworths has apologised for "inadvertently" stocking a singlet which says "if you don't love it, leave" alongside a picture of the Australian flag in two of its stores.

A photo of the singlet has gone viral on social media since it was posted on Sunday afternoon on Twitter by Canberra man George Craig.

The 29-year-old was in the Queensland town of Cairns on an end-of-season fishing trip with his football team when he spotted the offending item in the Woolworths store on Spence Street.

"I was with a bunch of blokes on a footy trip, not one thought it was appropriate," Mr Craig told the ABC.

"We were genuinely shocked, not just that the sentiment still exists, but that such a huge company with huge reach across a diversity of communities would stock the product."

Dozens of people took to Woolworths' Facebook account to criticise the supermarket giant over the singlet, with many labelling it racist.

"I hope you lose customers over this. How irresponsible, divisive and narrow-minded. Disgusting," one person wrote.

Another wrote: "Your singlets saying 'If you don't love...leave' are disgusting and divisive. Please withdraw then from sale at once."

Singlet 'inadvertently' stocked: Woolworths

A Woolworths spokesman said the shirt was stocked inadvertently in the Cairns shop and another in Sydney.

"It has come to our attention that two Woolworths stores were inadvertently stocking a singlet that we consider totally unacceptable," the spokesman said.

"The singlet was not one we ordered. It was delivered to us in error and should never [have] been allowed on our shelves.

"We will review our processes to ensure this sort of error cannot happen again."

The spokesman said the singlet had already been withdrawn from shelves.

"The sentiment expressed on the singlet does not reflect the views of Woolworths," the spokesman said.

"Woolworths has a policy of doing the right thing, which means we believe in fostering an environment where everyone is treated with dignity, courtesy and respect."

Melbourne MP and Australians Greens Deputy Leader Adam Brandt shared Mr Craig's image on his own Facebook page, attracting more than 1,200 comments.

"Hundreds of you shared the image, called Woolworths and posted on their Facebook page. Thanks for standing up for inclusion and acceptance - Woolworths have listened," he wrote.

Rival supermarket chain Aldi earlier this year withdrew a controversial Australia Day T-shirt from sale following an outcry on social media.

The German discount supermarket chain had offered the T-shirt, emblazoned with the slogan "Australia Est. 1788" - a reference to the year the First Fleet landed in Sydney - as part of a range of Australia Day items.

Retail giant Big W followed Aldi's lead and withdrew the same shirt.