Canberra's employers have been warned to be alert to the danger of ''upward bullies''.

Workplace investigators say they are coming across an increasing number of cases where rogue workers terrorise their bosses with the threat of bullying or harassment claims and among many employers, the subject is taboo.

As the traditional work Christmas party season nears its height, human resources consultants are also bracing for a busy time in the New Year coping with the fall-out of festive indiscretions.

Workplace investigator Jo Kamira, who has conducted more than 1000 inquiries into allegations of employment misconduct, says ''upward bullying'' is a growing trend as employees become more aware of how damaging a harassment claim can be to a business.

''It is rife and it is something that is not talked about,'' Ms Kamira said.

''It's a really common occurrence and often we find out about it when we're called in to investigate someone's complaint and then find that the complaint is totally unreasonable and the complainant turns out to be the bully.''

A slack attitude to documenting interactions with problem workers often comes back to haunt managers, according to the former AFP officer.

''You'll get a situation where the boss asks someone to do something and they come back and say, 'you know what, you're bullying me,' and if there's no documentation the whole complaint goes ahead,'' she said.

Ms Kamira said her company Wise Workplace Investigations was increasingly called in by private sector workplaces struggling to cope with an increasingly complex workplace relations landscape.

''We're starting to do a lot more private sector [work] but when we started, it was very rare because a lot of the time the private sector would sort things out internally, it's the biggest change we've seen,'' she said.

Inter-generational squabbles were also causing headaches for bosses.

''Some managers come from the baby boom generation and we know the public service is getting older and with Gen X and Gen Y, the behaviour that they expect from their managers is different and sometimes, there's that gap,'' Ms Kamira said.

''Maybe the boomers might turn around and say 'take a teaspoon of concrete, princess and harden up'.

''But those problems have to be jumped on straight away, just in the same way you don't let kids squabble, you should do the same as a manager.''

The Tuggeranong mother-of-two and her colleagues are bracing for a busy time in January as employers count the cost of alcohol-fuelled incidents at festive season parties.

But Ms Kamira says many problems can be avoided if employees are warned of acceptable standards of behaviour before the booze starts to flow.

''If they're providing alcohol, then they must be responsible in the service of alcohol,'' she said.

''Staff need to be aware that the obligations might extend a little bit further, perhaps if the work Christmas party kicks along somewhere else afterward.''