A consumer advocacy group warned yesterday that Washington area residents should prepare for high prices and long delays in home heating oil deliveries this winter because of low inventories, but an industry group predicted adequate supplies.

Joan Claybrook, president of Public Citizen and cofounder with Ralph Nader of Buyers Up, a Washington-based consumer fuel oil project, told a news conference that "record low inventories of home heating oil" will leave local homeowners "waiting in the cold for oil deliveries . . . and when they purchase their oil, they'll be forced to pay through the nose for it."

Jason Adkins, director of Buyers Up, estimated that low inventories could add another $200 to the annual cost of heating a home with oil this winter. He said the average metropolitan household already spends at least $1,000 a year to heat with oil.

About 26 percent of the 1.1 million households in the Washington area depend on heating oil, said Adkins, who has tracked heating oil prices in the region for the past year.

Claybrook said home heating oil inventories in the Washington area now are about 10 percent lower than last year and 20 percent below 1982 levels. That this could happen when there is an international oil glut and world prices are down suggests that there could be a "contrived shortage of heating oil supplies," she said.

"I'm not calling it a conspiracy . . . but there is a mentality of gouging by the oil industry," Claybrook said.

The Petroleum Marketers Association of America, a Washington-based trade group of independent heating oil and gasoline companies, said their members anticipate adequate suplies this winter.

Mark Decker, a vice president of the group, declined to comment on prices for the coming winter. "We can't talk about future prices, because of antitrust restrictions," he said. "All we can do is look at published price studies of what has happened in the past, and those show that the average price of heating oil nationally has declined about 28 percent since 1981."

Decker acknowledged, however, that prices for heating oil traditionally climb during the winter.

Buyers Up is a nonprofit organization started last year to help consumers buy heating oil at reduced prices -- usually 10 to 30 cents a gallon below the regular retail price, according to Adkins. Last year, that worked out to savings of $100 to $300 for the heating season for a typical customer, he said.