Amazon says its Prime Air drone delivery service will begin to drop off customer orders "in a matter of months".

The retailer made the announcement at its Re: Mars conference and published new test flight footage, showing how the electric six-rotor flying machine can fly up and down like a helicopter, and forwards like an airplane.

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Safety of such a device is critical, and to that end Amazon said the Prime Air drone's safety systems make it as "robust and stable as commercial aircraft".

Jeff Wilke, chief executive of Amazon's consumer worldwide division, said: "We know customers will only feel comfortable receiving drone deliveries if the system is incredibly safe".

Thermal cameras, depth cameras and sonar are used to spot hazards, while machine learning and an onboard computer identify obstacles and plot a flight path around them. Wilke added: "From paragliders, power lines, to the corgi in your backyard, this drone has safety covered."

To further ensure the safety of its drones - as well as other aircraft and passers-by on the ground below - Amazon has created what it calls an "automated drone management" system, but hasn't given details on how this will work, and if it will interact with existing air traffic control systems.

The company says it has run "millions" of simulations to help teach its drones how to deal with all manner of situations when it attempts to land and deliver a package. If the customer is spotted too close to the landing zone, the drone will hover and wait until they have moved safely out of the way. The drone's rotors are covered to prevent damage and injury.

Amazon says the drones will be capable of carrying packages weighing up to five pounds to addresses within a 15-mile radius of a fulfilment center, and within 30 minutes of the order being placed.

While five pounds may not sound like much, Amazon says this represents between 75 and 90 percent of all items ordered from its website.

Amazon did not expand on its goal to have Prime Air up and running "in a matter of months", but said it aims to have a certified commercial program that will allow it to deliver to customers in the coming months. Amazon has been working on drone deliveries since at least 2013, and announced it had complete its first delivery, in a rural part of Cambridge, England, in 2016.