FACEBOOK pages are being used to discredit people in Family Court proceedings and one in five cases now feature photos or comments that have been posted online, lawyers say.

Family law experts say social media sites are a form of character record and spouses are filing information from Facebook with the court through affidavits to discredit the other party.

Legal Services Commission family law manager Graham Russell said it was common for parties to supply print-outs from social networking sites to solicitors to display behaviour. "There has been a big increase in Facebook pages being filed in court to show off the bad behaviour of the other party," Mr Russell said.

"It is helpful to the court in exposing the comments and character of the people who are saying these things.

"They are putting themselves at risk of inferences being drawn about how well behaved they are or what attitude they have toward the other party."

Tindall Gask Bentley partner and family law specialist Dina Paspaliaris said social media material was especially prevalent in custody disputes over children in both the Family and Federal Magistrates courts.

"They have to be careful with what they are posting," Ms Paspaliaris said. Anything they're posting can be up for disclosure (to the court)."

She said lawyers now warned clients about social media records being accepted by the courts.

"(The material) is there, making an appearance in about 20 per cent of our files," Ms Paspaliaris said.

Law Society of SA president Ralph Bonig said courts were trying to accommodate advances in technology that had impacted on about one in five cases.

However, he said there were concerns about the legitimacy of material that did not yet meet the traditional standards of proof.

"By the old rules of evidence, in some cases, you would say you can't use this material because its authenticity and accuracy is questionable," Mr Bonig said.

"But it's probably one step better than oral evidence that comes down to he-said-she-said arguments."

He said people needed to be aware that when something was published on social media sites, even under secure settings, it could be available to the world.

"They are giving away what used to be seen as basic rights to privacy," he said.

Originally published as He said, she said - it's on Facebook