A witness to an incident that saw The Warehouse staff kick an alleged shoplifter on the ground has defended the workers, saying video footage does not capture the full story.

The Warehouse is investigating the incident at a Hamilton store on Saturday, which went viral after footage was posted on social media.

The witness told the Herald that she believed staff had acted appropriately to detain him while waiting for police to arrive.

The woman was outside the Hamilton store when she saw a man running out of the shop with a trolley full of goods.

"I went there to get cash out from the ATM outside ... I turned around and saw a guy running with a trolley full of stuff into a white people mover," the witness said.

She watched as a security guard came running out of The Warehouse and approached the alleged shoplifter.

As the suspect was loading items into the people mover, security staff had tried to retrieve the stolen items. However, the alleged thief then became aggressive towards the guard.

"The guy was abusing the guard and slamming the car door."

While attempting to wrestle the goods back, the security guard asked the suspect; "What are you stealing for?"

According to the witness, two girls inside the van quickly drove off - leaving the suspected thief in the hands of The Warehouse staff.

The witness then ran into a nearby shop and police were called.

The suspect remained on the ground, shouting and being verbally abusive towards The Warehouse staff as they waited for police to arrive.

Despite backlash on social media over a video of The Warehouse staff kicking the alleged shoplifter, the witness defended their actions.

"He [the suspect] was the one who was being violent towards them. They [The Warehouse staff] were doing their job, holding him down waiting for police," the witness says.

"He was being held accountable … They did nothing wrong."

The Warehouse said in a statement that the situation occurred after an alleged shoplifting incident at their Hillcrest store.

"We called the police and are co-operating with their inquiries. We're also fully investigating the incident ourselves, with urgency," a Warehouse spokesperson said.

The video has been watched more than 45,000 times and has been shared over 500 times.

The video has been reported to police, who say they are investigating. They have also obtained the video footage of the incident.