This is the only picture of the Tesla Semi released thus far by Elon Musk.

Palo Alto, Califiornia - Tesla chief executive Elon Musk said the electric carmaker was tentatively scheduled to unveil its planned semi-truck late in October, about a month later than the billionaire had earlier estimated.

"Tesla Semi truck unveil & test ride tentatively scheduled for Oct 26th in Hawthorne," Musk said in a tweet on Wednesday.

Musk has tantalised the trucking industry with the prospect of a battery-powered heavy-duty vehicle that can compete with conventional diesels, which can travel up to 1600 kilometres on a single tank of fuel.

Tesla's plans for new electric vehicles including a commercial truck called the Tesla Semi were announced in 2016 and in April Musk said the release of the semi-truck was set for September.

Tesla has been making strides in self-driving technology and implementing it in an electric truck could potentially move it forward in a highly competitive area of commercial transport also being pursued by Uber Technologies Inc and Alphabet Inc's Waymo.

Tesla was developing a long-haul, electric semi-truck that could drive itself and move in "platoons" that followed a lead vehicle, according to an email discussion of potential road tests between the car company and the Nevada Department of Motor Vehicles in August.

Tesla's electric big-rig truck could have a working range of 300-500 kilometres to compete with more conventional diesels.