The Foyle candidate said that the deeply personal abuse received by candidates so far, predominantly women, is totally unacceptable and parties have a duty to inform their activists that it will not be tolerated.
DUP Upper Bann candidate Carla Lockhart received a torrent of online abuse about her looks over the weekend by internet trolls.
Said the Foyle MLA: “The abuse levelled at candidates in this election so far has been absolutely disgusting.
“No one should be subjected to deeply personal insults, jibes and abuse for having the courage to stand before the electorate.
“The abuse from anonymous individuals not brave enough to put their name to their views is particularly insidious and threatening.
“It’s one thing to condemn it, all parties need to demonstrate that they are taking this issue seriously.
“That’s why I have written to all SDLP representatives, activists, canvassers and party members today instructing them to refrain from any and all comments or attacks which could be perceived as personal or abusive.
“We have a duty to ensure this campaign is a positive battle of ideas, our ambition for debate should be raised higher than the gutter.
“All parties should commit to taking robust action against those involved in this activity.
“The SDLP will not be found wanting,” added the SDLP leader.