D.C. Mayor Marion Barry yesterday delivered $200, some Christmas toys and a promise of swift action to a Southeast Washington family that was wrongfully terminated from the food stamp program because of a city welfare agency blunder.

The mayor visited the home of Ethel and Irving Winslow at the Potomac Gardens housing project after the story of the bureaucratic foul-up appeared Christmas morning in The Washington Post.

"I read these things, and I see that the bureaucracy is wrong," Barry said, "I get the impression city employes were just passing the buck. It seemed like they just processed paper and didn't solve the problem."

Ethel Winslow, a 32-year-old mother of six whose household also includes a 2-year-old granddaughter, had not received her $279 monthly food stamp allotment for two months because workers at the Department of Human Services incorrectly filled out forms and a computer then sent Winslow a termination notice, DHS officials said.

Despite dozens of phone calls, Winslow's benefits have not been restored, she said. Winslow, who receives $600.30 monthly in Aid to Families with Dependent Children, said she was forced to spend all the AFDC money on food and couldn't afford to buy her customary Christmas gifts or a real Christmas tree.

Barry said he had known Winslow for roughly 10 years through community anti-poverty work. She said she had been a volunteer canvasser and telephone caller in Barry's 1978 campaign. The mayor said he would have visited the family even if he hadn't known them, because the treatment they received from the bureaucracy "is just not right."

The mayor said he would demand an explanation for the delay on Monday. "I have said all along that we have responsibility to do all we can to solve problems and not just pass them along."

Barry, who spent most of Christmas at his home in Southeast Washington, said he drove to Potomac Gardens with his 18-month-old son Marion Christopher and had not sought to publicize the visit. He talked with a reporter who had called the Winslows and, after learning Barry was there, asked for the mayor.

Barry said the $200 gift came from his "constituents' services fund," which consists of donations rather than tax revenue. He said he uses the money for such problems as the Winslows' and for flowers and other small items.

Winslow, who also received several gifts of food, clothes and toys from anonymous donors, said following the mayor's visit, "Things are cheering up a little for the children."