Philadelphia Mayor Jim Kenney has banned all city employees from travelling to North Carolina and Mississippi in response to the "discriminatory laws" against members of the LGBT community in the two states.

Mississippi earlier passed a religious freedom law that allows religious organisations to refuse service to gays in weddings, adoption and foster care.

North Carolina also passed a bathroom law that allows people to use public restrooms only according to their biological sex.

"Discriminatory legislation, like those signed into law in North Carolina and Mississippi, is antithetical to our country's core democratic values," the Democratic mayor said. "By issuing a non-essential travel ban to those states, we take a stand against bigotry and prejudice happening in those states, and in cities and states nationwide."

Kenney said he welcomes any people, business, organisation and events that "no longer feel welcome in their state because of these discriminatory laws."

Helen Fitzpatrick, the state's Office of LGBT Affairs director, described the travel ban as "a powerful way for Philadelphia to stand in solidarity with, and advocate for, the LGBT folks and their allies living in cities and states passing discriminatory and dangerous legislation."

Kenney directed all city departments to "prohibit all travel to the states of North Carolina and Mississippi by city employees for purposes of official business."

He said the ban includes publicly-funded travel by city employees to the two states unless it is deemed as essential to public health and safety.

Kenney said he will lift the "ban if and when North Carolina and Mississippi choose to repeal their discriminatory legislation."

He has joined the Mayors Against Discrimination coalition, a group that promises to use their influence to oppose discriminatory practices in the U.S.

Initiated by San Francisco Mayor Edwin Lee, the coalition members also include New York City Mayor Bill de Blasio, Seattle Mayor Ed Murray, Portland Mayor Charlie Hales and Los Angeles Mayor Eric Garcetti.

Kenney also issued travel bans to Tennessee and Oxford, Atlanta also because of LGBT laws in those placed.