Allied Security is investigating after one of its security guards was filmed on CCTV beating up a homeless man outside a Wellington supermarket.
The video, uploaded to YouTube, shows the security guard talking to the homeless man, who is lying in a sleeping bag outside what's believed to be the Lambton Quay Countdown.
The homeless man jumps to his feet and throws a punch at the security guard, who then pushes the man into the wall. The pair fall to the ground and the guard can be seen pinning the man on the ground and punching him repeatedly. They then tussle on the ground as numerous pedestrians walk by.
The incident is believed to have happened on January 10.
A security industry insider who viewed the footage said he was "shocked" and called the guard's behaviour "unacceptable".
He had spoken with Countdown staff himself and believed the homeless man had been provoked.
"He did instigate the fight but the security guard took it further by basically assaulting him."
He said the incident was "quite shocking".
"That's excessive force and obviously puts a bad name on everyone else."
He was unhappy with how the security company, Allied Security, handled the situation.
Allied Security has not responded to requests for comment.
A Countdown spokeswoman would not comment on whether the security guard would be disciplined.
"We were very distressed to see this incident outside one of our stores," she said in a statement.
"This is a busy part of the central city, so while we do experience issues with people sitting outside our store sometimes, it's our absolute expectation that people are treated with dignity and respect.
"Regrettably our processes weren't followed on this occasion and our contracted security company is investigating this.
"Any specific questions would need to be directed to Allied Security."