A Florida jury has found Tesla liable to pay US$243 million to victims of a 2019 fatal crash of an Autopilot-equipped Model S, a verdict that could encourage more legal action against Elon Musk's electric vehicle company.

The verdict is a rare win for victims of accidents involving Autopilot. Musk has been pushing to rapidly expand Tesla's recently launched robotaxi business based on an advanced version of its driver assistance software.

Jurors in Miami federal court awarded the estate of Naibel Benavides Leon, as well as her former boyfriend Dillon Angulo, US$129 million in compensatory damages plus US$200 million in punitive damages, according to a verdict sheet.

Tesla was held liable for 33 percent of the compensatory damages, or US$42.6 million.

Jurors found the driver George McGee liable for 67 percent, but he was not a defendant and will not have to pay his share.

"Tesla designed Autopilot only for controlled-access highways yet deliberately chose not to restrict drivers from using it elsewhere, alongside Elon Musk telling the world Autopilot drove better than humans," Brett Schreiber, a lawyer for the plaintiffs, said in a statement.

"Today's verdict represents justice for Naibel's tragic death and Dillon's lifelong injuries," he added.

Tesla said it will appeal.

"Today's verdict is wrong and only works to set back automotive safety and jeopardise Tesla's and the entire industry's efforts to develop and implement life-saving technology," the company said.

The plaintiffs had sought US$345 million of damages. Their lawyers said the trial was the first involving the wrongful death of a third party resulting from Autopilot. (Reuters)