A landmark employment ruling should send a warning to businesses about privacy.

A recent Employment Relations Authority decision accepted 'secret' recordings made by an employee as evidence.

A woman left a cellphone in a room that other staff members were in, and recorded their conversation.

Simpson Grierson associate Rachael Judge said it's standard for the authority to accept secret recordings made by employees while in a meeting with their employer.

What's important to note about this case, is that the secret recording was made without the person in the room:

"She had left a cellphone in a room while other staff members were speaking and had secretly recorded their conversation, to obtain proof that there was gossiping and bullying towards her by other staff."

Recordings made when someone leaves their phone recording in a separate room, unbeknownst to others in the room, are not typically accepted.

"Our advice is that employers have a policy in place that makes it really clear that such behaviour is unacceptable in the workplace, because it's a breach of privacy of the other employees."

Judge said the staff who were recorded would not be able to bring a breach of privacy claim against the employee who recorded them, as she is an individual rather than an 'agency'.