'Unfriending' a colleague on Facebook amounts to workplace bullying, an industrial relations tribunal has ruled.

The decision emerged from a case involving two workers at a real estate agent's office in Tasmania and - Rachael Roberts, who had worked there for ten years, and sales administrator Lisa Bird.

The two initially had disagreement over who was to blame for a lost sale, The Australian newspaper reported, after which Mrs Bird stopped saying ‘Good morning’ to her colleague and unfriended her on Facebook.

A realtor who 'unfriended' her colleague after an argument was found to be bullying her workmate

The Fair Work Commission's Nicole Wells ruled Mrs Bird had behaved in an ‘unreasonable’ manner and shown a ‘lack of emotional maturity.’

Ms Roberts had complained to James Bird, the boss of the agency, the View, in Launceston – and husband of Mrs Bird - that she was not getting a fair representation of her properties displayed in the front window of the agency, the paper reported.

In response, Mrs Bird called a meeting with Ms Roberts where she accused her colleague of being a ‘naughty little schoolgirl running to the teacher’.

Ms Roberts left the meeting in tears, and said she checked Facebook minutes afterwards to see if Mrs Bird had posted any comments about the incident.

She found that Mrs Bird had deleted her as a Facebook friend.

‘Mrs Bird took the first opportunity to draw a line under the relationship with Ms Roberts ... when she removed her as a friend on Facebook as she did not like Ms Roberts and would prefer not to have to deal with her,’ the Fair Work Commission‘s Nicole Wells ruled.

She concluded that the act of ‘unfriending’ during the incident last January was evidence of ‘a lack of emotional maturity and is indicative of unreasonable behaviour’.

Calling her a ‘schoolgirl’ was ‘provocative and disobliging’, she added.

Ms Roberts was diagnosed with depression and anxiety and received medication and treatment from a psychologist and deemed unfit to return to work until the dispute had been resolved.

The tribunal found this showed Mrs Bird’s behaviour posed a risk to the employee’s health and safety.

The Fair Work Commissioner ruler the victim's health and safety was at risk after she suffered from depression and anxiety

It rejected the employer’s argument that an anti-bullying policy and manual had been written since the incidents and there was no risk of bullying occurring in the future.

Ms Roberts and the employer will have a conference to discuss what sort of anti-bullying order should be made.