The data watchdog is looking at whether Facebook secured personal information as it applies for a warrant to search computers and servers used by Cambridge Analytica (CA) amid concerns about the firm's activities.
Information Commissioner Elizabeth Denham told BBC Radio 4's Today programme: "We are looking at whether or not there was sufficient consent for individuals to be able to share their data with the application in the first place.
"We are looking at whether or not Facebook secured and safeguarded personal information on the platform and whether when they found out about the loss of the data, whether they acted robustly, and whether or not people were informed.
"So, we are looking at all of those strands."
Ms Denham said the watchdog had intervened to ask Facebook to withdraw from searching CA's offices, saying: "We are seeking a warrant so that, as the regulator, we can go in and get to the bottom, search the servers, do a data audit, and by Facebook going in at this point we were concerned about the integrity of our investigation.
"We are also looking at Facebook at the same time, so our advice to Facebook was to back away, let us get in there as a regulator and do our work, and they have agreed."
Ms Denham added: "There are provisions in the Data Protection Act that require a platform like Facebook to have strong safeguards in place. So, we are looking at whether or not there were safeguards, and whether or not Facebook acted appropriately when things went wrong."
The Information Commissioner said: "The allegation is that Cambridge Analytica acquired personal data in an unauthorised way and the Data Protection Act in the UK is a strong law, it's getting stronger, but we are looking at whether or not there was sufficient consent for individuals to be able to share their data with the application in the first place."
Asked if she had enough powers, Ms Denham said: "I am currently using all the tools in my toolbox, all the powers I have under the law, and my powers are about to get stronger."