Video of a huge spider crawling around inside a packet of Woolworths salad has gone viral on social media.

Sydney woman Zoe Perry shared a short video of what appeared to be a huntsman spider moving inside the bag of Italian salad she claimed she bought from a Woolworths store.

Within minutes of her post to the Woolworths Facebook page, the video attracted tens of thousands of comments and "shares".

After 12 hours, the video on the post from the self-confessed "arachnophobic family" was viewed more than 3 million times.

"Jesus, it's reanimated," a voice can be heard in the six-second video as the spider wriggles its eight legs.

More than 100,000 people commented on the video, some asking if the spider was returned to the garden, others defending the supermarket.

"As an ex-chef, I'm not at all surprised. All sorts of garden animals come in with produce. Snails, spiders, lady bugs, caterpillars, crickets and then some," Facebook user Daryl Hehir-Nielsen said.

"I would've been a bit startled, but I would have put him out into the garden and just washed the salad as usual," Kay Kelleher wrote.

Others Facebook users attempted to draw parallels with Thursday's recall of prepacked lettuce.

The Italian salad mix was not one of the 24 products to be taken off Woolworths and Coles shelves after a salmonella outbreak.

In a statement to the ABC, Woolworths said it required suppliers to follow quality control guidelines during food processing.

"Pre-packaged lettuce goes through an extensive process before being packaged," a Woolworths spokesman said.

"Our suppliers wash, blow dry, shake and visually inspect the lettuce."

A food quality expert was immediately sent to the processing facility to seek out options to ensure the incident did not happen again after Ms Perry's video was posted online.

"The customer has been contacted and an investigation is currently underway," the Woolworths spokesman said.

The ABC contacted Ms Perry for comment.