Twelve motorists have been prosecuted in WA for providing false and misleading information in relation to motor-injury insurance claims.

The cases include people claiming for lost wages while working, as well as exaggerating the extent of injuries. The Insurance Commission of Western Australia (ICWA) says the court action has saved more than $3.1 million.

One motorist who said back pain had stopped him working for two years – as well as fishing, camping and four-wheel driving – was seen in video footage pushing and lifting the bow of a boat to release it from its trailer during a fishing trip. He pleaded guilty to providing false and misleading information about his motor injury insurance claim.

Another motorist claimed to his doctor that he required the use of a neck brace and walking sticks, yet was filmed using no aids the day prior to attending the doctor's appointment.

A third motorist was fined $4000 after he made three requests for lost wages but took an international holiday and worked for a taxi company. He pleaded guilty to four charges of providing false and misleading information about injuries he sustained in a car crash in May 2017, and was also fined for falsely advising his doctor he was unable to work.

A further seven cases are to be heard in the Magistrates Court later this year.

Treasurer Ben Wyatt says ICWA released the results of the prosecutions to remind all claimants to be honest when making a motor injury claim.

"It's not worth the risk of a criminal conviction, the fine, and consequences that come from breaking the law and appearing in court,” Mr Wyatt said.

Providing false or misleading information to ICWA can result in a criminal conviction and a fine of up to $10,000.