DJ Larkin of the Pivot Legal Society says the lawsuit has been filed in B.C. Supreme Court in New Westminster on behalf of a group known as the BC/Yukon Association of Drug War Survivors.
She says the action is a response to the city's efforts to obtain a court order that would make it illegal to erect a tent in any park in the city.
The society says in a news release that homeless people have suffered for years, have had their tents and structures destroyed, chicken manure spread where they have lived and been pushed from relatively safe places to more "dangerous conditions."
None of the allegations have been proven in court, and a spokeswoman for the city was unable to comment because she says the city had not yet seen the lawsuit.
Pivot says the Drug War Survivors will be back in court at the beginning of April to set a trial date and will be asking for the case to be heard in this summer.