Striking unions could face restrictions on their use of social media, the TUC's general secretary has told the BBC.
Frances O'Grady said an attack on trade unions was "unfinished business" for "some elements within governments".
Ministers said any restrictions would not apply to posts by individuals.
The proposed restrictions are part of wider proposals to tighten the law on strikes, which ministers say will reduce disruption for the public.
The consultation document suggests unions taking industrial action must give notice of "whether it will be using social media, specifically Facebook, Twitter, blogs, setting up websites and what those blogs and websites will set out".
The outline of the Trade Union Bill was published last month - including proposals for a minimum 50% turnout in any strike ballot - but the finer details of the proposals are subject to a consultation period.
Ms O'Grady said: "I think most people feel that the police should be out there catching burglars.
"We shouldn't be wasting police time, and I suspect many police officers... would rather be out doing the job that they joined the police service to do, rather than checking Facebook pages and Twitter accounts.
"I think there are elements in the government who see an attack on trade unions as unfinished business, but I don't think the country is with them and I think there are growing concerns about the civil liberties implications of trying to undermine fundamental rights, human rights, like the right to strike."
Minister for Trade Unions, Nick Boles, said while the ability to strike is important, there should be a balance between the interests of union members and those who depend on their services.
"People have the right to know that the services on which they and their families rely will not be disrupted at short notice by strikes supported by a small proportion of union members," he added.