The official portraits of former president Richard Nixon and his wife, Pat, were hung in the White House yesterday, more than seven years after Nixon left office.

According to a White House spokesman, the portraits -- which cost $15,000 each -- took this long to get to the White House because the former president did not sit for his until earlier this year.

"Mrs. Nixon's was completed in 1978," the spokesman said, "but I understand she did not want it hanging in the White House until her husband's was finished."

Richard Nixon's portrait was painted by artist Alexander Clayton, a Chevy Chase, Md., native who now lives in Dallas, Tex. It shows him sitting behind a desk wearing a dark blue suit, and was hung on the state floor of the White House along with the portraits of other past presidents.

Pat Nixon's portrait, by Henriette Wyeth Hurd, was hung in the hallway outside the diplomatic reception room across the doorway from Betty Ford's portrait. It features the former first lady sitting in a three-quarter pose, wearing a light blue dress.

The portraits were paid for by the White House Historical Association, which raises funds through the sale of White House guidebooks.

Hurd, sister of artist Andrew Wyeth and wife of painter Peter Hurd, was initially supposed to paint Richard Nixon's portrait as well. Last year she was quoted as saying that she would not paint him from old photographs as he had requested. He eventually did sit for Clayton's portrait this year in New York City.

Hurd had said that she was anxious to paint the couple's portraits and couldn't understand other painters who sit "in chilly judgment" of Nixon. She painted Pat Nixon's portrait in late 1978 at the Nixon's former residence in San Clemente, Calif.

The former president had wanted Andrew Wyeth to paint him, but the two could not coordinate their schedules.

One White House aide said the Nixons would not be coming to see the portraits in place. Late yesterday, Nancy Reagan's press office issued a "media advisory" that the portraits had gone on view. It was an unusually low-key approach to the event, which in the cases of other past presidents and first ladies has been noted with considerably more attention.