Mayor Marion Barry and a coalition of homeless advocacy groups launched a drive yesterday to raise $150,000 to provide emergency assistance to homeless people to supplement funds already provided by the D.C. government and private groups.

Barry said he hoped residents who overwhelmingly approved an initiative last November requiring the city to guarantee emergency shelter for all homeless people would contribute to the fund.

"Now is our chance to vote with our wallets and show that concern in a clear and concrete way," Barry said at a kickoff for the drive at the District Building.

The mayor later told reporters that the District does not intend to drop a lawsuit in D.C. Superior Court challenging the legality of the homeless initiative.

Officials contend that the initiative is an improper encroachment on the District's budget authority because it potentially commits the city to spending millions of dollars to provide shelter for the homeless.

"We have to protect our legal options," Barry said. "We're going to move ahead [on the suit] .. . . We have to make sure we don't have any [adverse] legal precedents set here."

The Community for Creative Non-Violence, the nationally known advocacy group that sponsored the initiative, is not participating in the fund-raising effort. Mitch Snyder, a leader of CCNV, criticized Barry for trying to create the impression he is alleviating the problems of the homeless while fighting the initiative.

Snyder said that Barry and other big city mayors "are not willing to face up" to the problem and that they are "inclined to do things that at least give the impression of motion and action, when really nothing is happening."

"The city government finds itself trapped between a rock and hard place and its best approach is appearing to do something when they're doing nothing," he said.

The D.C. government is spending about $3.6 million this year to provide emergency shelter for homeless men and women. Barry has proposed a fiscal 1986 operating budget that would increase spending for the homeless by nearly $1.9 million. Under the mayor's plan, the city would increase the number of persons assisted from 5,196 this year to 6,077.

Yesterday, Barry declared February "Friends of the Homeless Month" during a meeting with Ma rie Nahikian, chairperson of the Coalition for the Homeless, and others taking part in the private fund-raising effort.

Nahikian said the funds would be used to meet emergency financial needs of the homeless, including covering the cost of utilities, heat and water at shelters, without having to go through a lot of government red tape.

More than $9,000 was contributed yesterday, including $5,000 in city funds pledged by Barry and $1,000 apiece from Woodward & Lothrop, Washington Gas Light Co. and Chesapeake & Potomac Telephone Co.

The Arab American Business Association of North America and the Arab American Anti-Discrimination Committee contributed a total of $700, USAir gave $500 and Safeway Inc. donated 10,000 pounds of food.