Justice Secretary Chris Grayling has warned that Twitter users who libel individuals on the social networking site face the same laws as newspaper editors.
Mr Grayling told MPs, "It is utterly, utterly wrong that anybody should have their name blackened, inappropriately and falsely, on any form of social media".
Speaking after a report on BBC's Newsnight led to Lord McAlpine wrongly being branded a child abuser, the Justice Secretary said he is "as concerned as anybody else about what has taken place over the last two weeks".
"The laws of libel apply equally to what you publish on your Facebook page or Twitter page as they do in a printed form," Mr Grayling said. "Those who are damaged in that way have full legal redress to try and get proper justice".
More top news
David Cameron said the June 23 referendum is the most important vote young people will place in their lifetimes.
Plan would leave steelworkers worse off in retirement - but not as worse off as those in other pension schemes.
Donald Trump has labelled Hillary Clinton "crooked" and says he cannot wait to face her in November's US presidential election.