Parker said on Wednesday there is "no limit" to how Amazon is storing and listening to private conversations, adding that these recordings "could potentially be used against you in a court of law or for other purposes."
"If you're having a conversation in front of an Alexa-enabled device, Amazon is not guaranteeing you any privacy," Parker said in a discussion on stage with CNBC's Hadley Gamble at the Milken Institute MENA Summit.
Amazon came under fire last year when an Echo device reportedly secretly recorded a family's conversation and sent it to a random person. Amazon blamed the incident on Alexa misinterpreting a set of commands.
A spokesperson for Amazon told CNBC that customer trust is of the utmost importance, sit takes privacy seriously.
"By default, Echo devices are designed to only capture audio after it detects the wake word. Only after the wake word is detected does audio get streamed to the cloud, and the stream closes immediately after Alexa processes a customer request," the spokesperson said in an emailed statement.
"No audio is stored or saved on the device. Customers can also review and delete voice recordings."
Speaking to CNBC last month, Amazon's VP of Voice Pete Thompson said that his company was taking security and data privacy extremely seriously.
"Even when we put Alexa into our partner products that's something that we mandate of how they can do, how they can use this stuff. Obviously it is early days on how voice works and some of the biggest challenges is when you speak to it hands free, and you are talking to it from a distance. We try very hard to tune it, to make sure we've only heard 'Alexa' and then that's when it wakes up .. we have to keep improving that," he said.
Facebook, meanwhile, is facing mounting regulatory concerns amid questions over how it collects user data. Last week, Germany's antirust watchdog ruled Facebook cannot combine data from its various apps, like WhatsApp and Instagram, without voluntary user consent.
Parker said it is against tech companies' own financial interests to police themselves on data privacy and security.
"If the public dialogue doesn't change these companies' behavior then...it becomes a government issue," he said.
Parker, who is also the founder of Napster, left Facebook in 2006 after less than two years on the job. He was also an early investor in Spotify and served on the music-streaming giant's board until 2017.
He founded the Parker Institute for Cancer Immunotherapy in 2016 to research and develop better treatments for cancer.