Multi-million pound Northern Ireland bus building firm Wrightbus has launched an investigation after video footage showing two men being pushed into the company's industrial bus wash was posted on the internet.
The Ballymena-based company launched the internal probe after the Belfast Telegraph published photographs of the video footage which had been recorded on a mobile phone and posted on the website YouTube.
The video showed two men being tied onto a trolley with cable ties and then pushed into a large bus wash.
As the men were pushed into the running water a crowd of people were captured standing around cheering and laughing.
It is understood that two people in the crowd are company managers.
A second video shows an unsuspecting employee getting a bucket of water thrown over him while he works. Several people can be heard laughing in the background.
Both videos have since been removed from YouTube.
A company spokeswoman told the Belfast Telegraph that Wrightbus is " strongly opposed to any acts of bullying, harassment, intimidation or inappropriate behaviour in the workplace".
She added: "In fact, this was recently reinforced by a training programme on the subject which all employees attended.
"The video of apparent 'horseplay' on the company premises is presently the subject of an internal disciplinary investigation, and those responsible will be dealt with in line with company policy."
However, one employee said people are afraid to make complaints about bullying in case they are the next to be targeted.
"These sort of videos are being taken all the time. It is not very funny for those who are the butt of the so-called jokes," he said.
Lyn Witheridge, chief executive of the Andrea Adams Trust - the first charity in the UK dedicated to preventing workplace bullying - described the video footage as "totally unacceptable".
"This footage is sickening. Is it fun? Is it high jinks? Well, I wonder what the people who were targeted really feel about it. Employers have a duty of care towards their employees so I hope this will be taken seriously," she added.
Wrightbus, which built the world's first hybrid electric double decker bus, is a highly successful family company based in Ballymena.