Some users have reported seeing a screen saying, "If you don't live with the owner of this account, you need your own account to keep watching."
A spokesperson told the BBC: "This test is designed to help ensure that people using Netflix accounts are authorised to do so."
A decision has yet to be made as to whether the company will roll this out across its network.
In the trial, users can verify they are allowed to access the account by a code, sent via text or email.
