The line becomes blurred for journalists whose job it is to report on news events for their employer.

The question of whether Scott McIntyre's dismissal was unfair would largely turn on whether his comments about Anzac Day were relevant to his relationship to SBS as a sports reporter. For example, it is unlikely an employer could sack an employee who declared they hated their mother on Twitter unless their mother was employed by the same company.

McIntyre, a soccer reporter, was sacked by the public broadcaster after posting comments about Anzac Day on Twitter that were described as "inappropriate and disrespectful".

He referred to some Australians marking Anzac Day as "poorly-read, largely white, nationalist drinkers and gamblers" on his officially verified Twitter account on Saturday night.

He also told his 30,000 followers that Anzacs in Egypt, Palestine and Japan were responsible for summary execution, widespread rape and theft.

McIntyre was sacked without notice, which means SBS may need to have alleged and proven serious misconduct on his part. SBS alleges he breached the SBS social media policy.

According to labour lawyers, there is no doubt an employee can be dismissed for a serious breach of a company policy that relates to their employment.

As a journalist, Mr McIntyre used his Twitter account to express personal opinions and for work purposes. There is a blurring between his sports and social commentary.

In sacking an employee, an employer may argue the employee was responsible for damage to the employer's reputation.

In a statement issued by SBS, it said "employees on and off air are encouraged to participate in social media, however, maintaining the integrity of the network and audience trust is vital. It is unfortunate that on this very important occasion, Mr McIntyre's comments have compromised both."

SBS said Mr McIntyre's views in no way reflect the views of the network which supports "our Anzacs and has devoted unprecedented resources to coverage of the 100th anniversary of the Gallipoli landings".

Mr McIntyre declined to comment.

In an article he wrote for Fairfax Media last year, Leigh Johns, a Fair Work Commissioner, warned employees about the risks of making comments on Facebook and other social media.

He said that every year, the commission hears and determines claims of unfair dismissal, where the employee has been sacked because of their activity on social media.

"Unless you are an employee who made a New Year's resolution to #losemyjob, using social media to telegraph to the world your dissatisfaction with your work, your job, co-workers, manager or boss is #dumbbehaviour," Mr Johns said.

"Where policies exist, employees should acquaint themselves with their employer's social networking rules and abide by them."

Mr Johns said each case will depend on its particular circumstances and facts. There have been other decisions where the commission has found that comments on Facebook amounted to "friends letting off steam" or were "private views" or were not specific enough to relate to the employee's employment.

"However, it is foolish of employees to think they may say what they wish on their Facebook page with total immunity from any consequences. There is no reason why the same principles would not be applied to Instagram accounts or other forms of social media," Mr Johns said.

"Employees are entitled to private opinions and to express them, but common sense should dictate discretion in the use of social media when it comes to events at work."