Democratic National Committee Chairman John C. White is still being investigated by a federal grand jury in New York, officials said yesterday, though he declined a potential bribe offer in 1979.

Possible perjury charges against White were not ruled out yesterday in court papers brought up during a hearing in which James C. Day, a Texas acquaintance, was sentenced to four years in prison for his part in a $1 million scheme to persuade the Libyan government that he could bribe top Carter administration officials to release some C130 planes

Prosecutor Raymond A. Levites told U.S. District Court Judge Richard Owen in a pre-sentencing letter that Day had falsely stated that White was prepared to take a $25,000 bribe to guarantee a favorable reception at the Department of Energy for a therman energy proposal in the fall of 1979.

In a meeting with an undercover FBI agent involved in the Abscam investigation, White never solicited the money and Day admitted later that White knew nothing of the planned bribe and that he intended to keep the money himself.

Later in the letter, however, Levites said that the government is planning to seek at least one perjury indictment of someone involved with Day's plotting. Levites refused to say if White is the individual referred to, but when asked if White is now out of danger of indictment, he said: "That's for the grand jury to decide. The decision has not yet been made."

White has appeared twice before a grand jury investigating the scheme to gain the release of the cargo planes the Libyans bought from the United States years ago. Libya never received the planes because it was branded a terrorist threat. White has acknowledged making several calls to State Department officials about the planes' status of Day's behalf.

White announced his resignation as party chairman after President carter's defeat last November but is still technically the Democratic boss until the end of the month, his attorney, Stuart Pierson, said yesterday. "In my estimation, they [the prosecutors] haven't concluded their investigation yet," he said. "Thus, I don't think they're talking about John" as the proposed target of the indictment.

Sen. Orrin G. Hatch (R-Utah ) said just before the election that White "absolutely" was a target of the New York grand jury.

Judge Owen told Day at the hearing that "You made false and fraudulent statements that you had the Democratic national chairman in your pocket and that you had a pipeline to Hamilton Jordan. This was not just puffery. This was fraud on the highest level.

"You got Mr. White to come to meetings so that he could be exhibited as your contact," the judge added. He went on to say, "It is bad enough when public officials are corrupt. But it is even worse when they are not corrupt and you say that they are."

The pre-sentencing letter also described other schemes in which day falsely boasted he had influence with federal officials:

He told reputed New Orleans organized-crime boss Carlos Marcello in mid-1979 that then-Immigration and Naturalization Service Commissioner Leonel J. Castillo "could be approached, for a fee through Day, to improperly interfere with pending immigration matters." Day later admitted Castillo knew nothing of his conversation with Marcello.

Castillo, who now lives in Houston, said yesterday that he doesn't recall discussing Marcello's immigration problems with Day.

He told the Libyans that he had access to CIA information on Libyan oil matters through White. This too was false, Day admitted later.