The deactivated pages include UK Uncut, and pages created by students during last December's university occupations.
A list posted on the Stop Facebook Purge group says Chesterfield Stop the Cuts, Tower Hamlet Greens, London Student Assembly, Southwark SoS and Bristol Uncut sites are no longer functioning.
Administrators for the profiles say hundreds of links between activists have been broken in the run up to the May Day bank holiday. When users click on URL links the message "the page you requested was not found" now appears.
Guy Aitchison, 26, an administrator for one of the non-functioning pages, said: "I woke up this morning to find that a lot of the groups we'd been using for anti cuts activity had disappeared. The timing of it seems suspicious, given a general political crackdown because of the wedding. It seems that dozens of other groups have also been affected, including some of the local UK Uncut groups."
It is not yet known how many groups have been affected in total. A Facebook spokeswoman explained that the profiles were suspended because they had not been registered correctly and denied that the removal of pages was politically motivated or instigated by law enforcement concerns before the royal wedding.
Facebook accounts that claim to represent individual people but are in fact groups or organisations contravene the company's "statement of rights and responsibilities".
The company said a number accounts were suspended at the same time.
Facebook uses technology to track relationships between groups and when one "fake" profile is found, pages that have links to it are also checked. This is done to maintain safety and security on the site and the removal of everything from fake celebrities to pages representing pets is a regular occurrence.
The company did not confirm how many activist accounts had been deactivated on Friday morning.
A spokeswoman for Facebook said activists would be contacted by email and told how to re-activate their accounts correctly. They said this would take several days.
Jim Killock, 38 who runs the Open Rights Group, which campaigns for civil liberties on the net, said: "It's pretty flatfooted of Facebook to pull profiles without notifying users. Clearly, if you just take down sites without any warning, people are going to feel aggrieved, they're going to have activities disrupted and be unable to organise politically," he said.
"It's a pretty bureaucratic move; it's almost impossible to know the difference between a profile and a page, so Facebook should have emailed people first and given them some notice. It's bizarre and upsetting and it's not a good way to treat their users," he said
source: guardian.co.uk