An woman in California was threatened with arrest and forced to leave a government building because a security guard took offence at her T-shirt.

Lapriss Gilbert, 31, wore a lesbian.com shirt when she went to collect a Social Security card for her son.

The guard, who works for Paragon Security, challenged her and forced her to leave the building.

Ms Gilbert contacted her mother who called the police but before they arrived she was readmitted and escorted to the front of the queue, the LA Daily News reports.

The security company is under contract to the Department of Homeland Security to guard the building in Van Nuys.

A department spokeswoman condemned the guard’s actions and said that Paragon had been contacted about the incident.

Ms Gilbert was reportedly told by the guard that he had jurisdiction over her clothing under the Rules and Regulations Governing Conduct on Federal Property.

In fact it makes no reference to clothing.

“As an African-American and a lesbian, I haven’t been through one day without facing some sort of discrimination … but this is just shocking” Ms Gilbert told the Daily News.