Staff should be warned they could face disciplinary action if they step over the mark at the office Christmas party.

They could fall foul of their employer's code of conduct for kissing under the mistletoe or getting drunk.

With just 10 working days to Christmas, and the party season in full swing, despite the harsh economic climate, Simon Warley, partner and head of the employment team at Dartford law firm Vizards Wyeth, says employers can avoid a human resource hangover if they follow some basic rules. If they don't, they could by liable for the actions of their staff.

He says festive revelries are fraught with potential legal pitfalls which employers should understand before the party is in full swing.

He urges them to remind staff about standards of behaviour and warn them that "disciplinary action may be taken if they step out of line."

They should also remember that office parties are an extension of the workplace even if they are held at a separate venue outside office hours. Employers have the same duty of care.

"Alcohol and a relaxed atmosphere mean things can quickly get out of control, with serious consequences for employers," Mr Warley said.

"Problems can range from drunken antics to fighting, drink driving and allegations of sexual harassment and assault. Comments made by employees, intended in humour but perceived by another employee to be offensive, could result in liability on behalf of the employer for harassment."

Any employees taking drugs will be committing a criminal offence but employers may be doing the same if they know that illegal drugs are being used or distributed on company premises.

Mr Warley's other tips for an incident-free party include limiting a free bar; providing information about taxis and public transport or arranging transport home; inviting partners of either sex to avoid discrimination; and being flexible about the time employees come to work the following day, especially if they drive or operate machinery.

• Mr Warley can be contacted for further advice at snw@vizardswyeth.com