Tokyo-based venture ZMP Inc. may begin field testing a self-driving delivery robot in August intended as an alternative to aerial delivery drones as Japan grapples with a growing labor shortage.

The box-shaped CarriRo Delivery robot, which is 133 cm long and 109 cm high, is designed to run on sidewalks and carry loads of up to 100 kg, ZMP said.

"Our delivery robot is more suitable than drones when it comes to delivering heavy products like food items," said ZMP Chief Executive Officer Hisashi Taniguchi.

The company has teamed up with sushi delivery firm Ride On Express Co. to test a prototype of the autonomous vehicle on private property.

The robot, which is equipped with cameras and sensors and can steer itself at a maximum speed of 6 kph, selects delivery routes on its own using a pre-loaded map. It can be controlled remotely when needed, according to ZMP, which is also developing self-driving car technologies.

Customers can unlock the robot's cargo hold using a code sent to their smartphones.

While looking to improve the robot's features, including climate management in the cargo hold, ZMP and its partners will urge the government to make regulatory changes that allow the robot to be tested on public roads.

ZMP hopes the CarriRo Delivery robot will be treated similarly to electric scooters used by the elderly.

Domino's Pizza Enterprises Ltd. began testing an autonomous delivery robot in Australia last year, while companies like Inc. and Rakuten Inc. are seeking to commercialize drones for door-to-door parcel deliveries.