A Queensland lawyer has warned that "claims harvesting" is happening in Australia and accident victims should be careful what they say in social media.

Claims harvesting involves marketers, who are not lawyers, trying to find people who have been in a crash and convincing them to file a claim, taking down the information and selling it on to a law firm as a case to pursue. The Accident Compensation scheme means the practice is unlikely to occur in New Zealand.

Travis Schultz of Travis Shultz Law is reported in the Sunshine Coast Daily as saying claims harvesting is illegal in Queensland, but some law firms are still treating it as "an ethical grey area".

"Typically they might go through some other entity in Australia, and that entity then contracts to a law firm to help with their marketing, effectively selling them people's data and the leads they've got through their harvesting activities," Mr Schultz says.

The Sunshine Coast Daily says that according to Mr Schultz, most claims harvesters will cold call residents at random, telling them they are calling about a recent car crash they or another family member had been involved in.

"In fact, I myself have had at least five or six phone calls over the last two years," he says. "I've had it reported to me by a number of other people."

Mr Shultz says harvesters are increasingly turning to social media to find targets. He says they trawl Facebook for any mention of a recent crash. The harvesters apparently give victims the impression that they are from an official service, and they may push the target into lodging a claim or sometimes providing inaccurate information.