Amazon on Wednesday began using a smart door lock and camera system to allow its drivers to leave packages inside clients' houses instead of on the porch.

The online retail giant insisted that the service is safe, despite being quickly rounded upon on social media for the new innovation, which it says will stop thieves stealing packages from outside homes.

The Amazon Key smart lock is fitted to a customer's door, allowing the delivery driver access to their home. The security camera then records the movements of the delivery person. The customer can watch the delivery take place in real time if wanted.

Upon arrival, the driver will have to access an app that will verify that the correct driver is at the right address at the intended time. Only then is the door unlocked.

Amazon says the new service will negate the need to have a family member or neighbor stay at home to receive your delivery, and can be used by house cleaners and dog walkers to access your home.

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The Cloud cam is being tested by Amazon Prime customers in 37 US cities before being rolled out nationwide. The camera, smart lock and installation costs $250 (215 euros).

But despite the hype, a survey by the tech website Recode found that 61 percent of Americans wouldn't entertain installing the system because of security fears. Among Amazon Prime subscribers, just 5 percent said they would definitely buy the lock/cam service.

Several people took to social media to mock the new service including Seattle-based TV host Bill Wixey.

"To avoid having people steal packages off our front porches, with #AmazonKey we can allow strangers inside our house....where they can steal everything." he tweeted.

A Twitter fan known as Juili Tonape described the new service as the "creepiest thing ever."

Another Twitter user, Michael Pace said Amazon Key was "potentially dangerous" but "likely to take over the world."

Meanwhile Jason Falter was concerned about delivery drivers disturbing pets.

"What if the delivery person lets out the dog or cat??? Think people!!! This is not a good answer for delivery." he tweeted.