Amazon is bringing delivery robots to the streets of a Seattle suburb.

The online shopping giant said it has started testing self-driving robots, named Scout, in Snohomish County, Washington that can bring Amazon packages to shoppers' doorsteps.

The robots are light blue, about the size of a Labrador, have six wheels and the Amazon smile logo stamped on its side, according to photos of the robot previewed by Amazon. Six of them will be roaming the sidewalks and streets of the neighbourhood and can navigate around pets and pedestrians, the company said.

"We developed Amazon Scout at our research and development lab in Seattle, ensuring the devices can safely and efficiently navigate around pets, pedestrians and anything else in their path," said Amazon vice president Sean Scott who is heading the project, in an official blog post introducing the delivery system.

"Customers in Snohomish County order just as they normally would and their Amazon packages will be delivered either by one of our trusted partner carriers or by Amazon Scout," Scott said.

Scout delivery robots will work only during daylight hours Mondays through Fridays, automatically manoeuvring to destinations but accompanied by Amazon employees, according to the company.

However, it didn't provide additional details of how the service would work and did not respond to questions about the test.

Chinese retail giant JD.com also uses delivery robots, as do a number of startups operating in the United States and Europe. Starship Technologies, based in Estonia, has tested operation in the US capital city of Washington, and another startup, KiwiBot, handles deliveries to US university students.