Sen. Harrison Williams (D.-N.J.) was scheduled to fly to New Jersey on a campaign trip with President Carter yesterday afternoon, but canceled his plans at the last minute after news reports of his imminent indictment on Abscam-related corruption charges.

Officials insisted that a delay of the planned presentation of the case to a federal grand jury in Brooklyn on Thursday was unrelated to the campaign trip. But the incident did leave several administration officials with red faces and raises questions about communications between the Justice Department and the White House on potentially embarrassing cases.

Justice Department officials said prosecutors delayed the grand jury presentation until early next week for logistical reasons totally unrelated to presidential politics.

White House spokesman Ray Jenkins said he did not know if the Justice Department warned the president of the potential indictment, but said "it is quite normal for the president to invite Democratic senators along on campaign trips to their home states."

In early afternoon, shortly before he was to join the president for the flight to New Jersey, Williams issued a statement saying that he had looked forward to the trip but had "become the subject of speculation in the press on an unrelated matter. Since the focus of the president's trip should be on the good message he will bring to the voters in New Jersey, I decided it would be best to cancel my plans."

A source close to Williams said the senator was aware of the potential indictment, but accepted the White House invitation because he wanted to try to help the Carter campaign in a crucial state. "They [White House officials] must have thought his [Williamsh] presence would help, not hurt," he said.

The Justice Department instituted a warning system to ensure that top administration officials would not be caught in embarrassing situations with targets of criminal investigations. The investigation of Williams has been public since February, however, and some Justice officials wondered why any further warning was necessary.