A legal expert is warning Tesla drivers using the car's new unapproved Autopilot functions that they are in danger of committing an offence and that insurers cannot cover accident costs. US-based electric vehicle manufacturer Tesla rolled out the new driver-assisted functions worldwide late last month. They allow Model S cars to automatically change lanes, change speed in traffic, steer within lanes and park with the help of radar, cameras and ultrasonic sensors. READ MORE: 'Hands-free' driving in Hong Kong: Tesla begins road-testing 'autopilot' mode, government yet to approve, SCMP takes it for a spin The Transport Department has cited the Road Traffic Ordinance in saying that all "software updates that would affect prevailing driving functions" must be approved by the authority after Tesla launched the update without government approval. "If the driver is using the car with such unapproved software, then he is committing an offence," said lawmaker James To Kun-sun, who is a member of the Legislative Council's transport panel. Watch: Can Tesla's new 'autopilot' system work in crowded Hong Kong? We did a test drive "Even if the driver doesn't know whether the software is approved, ignorance of the law is no excuse." While Tesla motorists cannot uninstall the software, they can choose not to activate its functions while driving. If accidents occurred and the investigation revealed that the driver was using the unauthorised software at the time of the accident, then he could be prosecuted, To explained. Tesla has stopped releasing the system update to drivers that have yet to download the new version, but have not restored an older software version as required by the Transport Department. According to figures given to the transport authority, there are a "small number of vehicles" which have downloaded the 7.0 Autopilot update. There are at least 2,000 Tesla vehicles in Hong Kong, but only a limited number of Model S cars are compatible with Autopilot. READ MORE: Insurance a legal grey area in Hong Kong for all-electric Tesla car's new Autopilot system Tesla refused to comment on the matter after repeated inquiries from the Post . The firm previously wrote in an email that it was "currently working with the relevant authorities to ensure a proper understanding of this new update". A representative from the insurance sector said that insurance would not cover accident costs since the software update had yet to obtain legislative approval. "We can only follow the law. We can't do anything if the law doesn't change," said Jimmy Poon Wing-fai, a governing committee member of the Hong Kong Federation of Insurers. Tesla driver Mark Webb-Johnson called on the government to specify which part of the law drivers are violating. "It's ridiculous to go all high and mighty against Tesla and other car manufacturers when it's not enforced in other places," he said.