According to Choice, third-party platforms such as Ignite, 2Apply and Snug regularly require users to hand over excessive amounts of personal data including bank statements, references from five jobs and photos of children.
Samantha Floreani, program lead at charity Digital Rights Watch, said: "The sheer volume and type of personal information that renters are being compelled to provide creates unreasonable privacy and digital security risks.
"It's often very unclear who gets access to this information, and how long it will be kept for."