A top White House official conceded yesterday that the Carter administration has been slow to fill top government positions, but also defended the lengthy selection process and said it is nearing completion.

Presidential assistant Hamilton Jordan summoned reporters to his office yesterday afternoon after a number of inquiries about the slowness in making presidential appointments to the under secretary and assistant secretary positions in executive branch departments.

According to Jordan and White House personnel director Jim King, appointments. These apointees, roughly one-third of the top policy-making officials President Carter will choose, have been confirmed by the Senate or are awaiting confirmation hearings, they said.

Jordan said 65 other appointees have been selected by the Cabinet secretaries and cleared by White House officials, including the President. They are now at various stages of additional background checks by the FBI, the Internal Revenue Service and White House lawyers who are reviewing the apointees' financial disclosure statements.

King said eight of the 65 cleared the background check process yesterday and that their nominations will now be sent to Capitol Hill.

In addition, Jordan said 10 to 15 policymaking jobs, which he did not identify, will not be filled because they are considered unnecessary.

There are between 160 and about 200 presidential appointments requiring Senate confirmation available to Carter, meaning he still has roughly 30 to 70 slots to fill.

Conceding that the process has taken "much longer than we would like it to," Jordan noted that the Kennedy and Nixon administrations filled all top jobs in four weeks, while the six-week-old Carter administration is still making appointments. But he said the President and other officials "are not going to sacrifice the process" they are following for the sake of speed.

"If we are going to be here for four years, we feel an extra week or two is worth it," Jordan said.

One new step in the selection process that Carter has imposed is the requirement that top officials complete financial disclosure statements before being nominated. Jordan also cited these factors:

In some cases, the Cabinet secretaries have been slow to choose their top assistants, with some selections not being made until mid-February.

FBI background checks have taken an average of four to tive weeks to complete.

Some apointees have slowed the process. Jordan cited the case of a high-ranking but still unconfirmed State Department apointee selected in December who did not get his financial disclosure data to the White House until this week.

The President's committment to increase the number of women and minorities in the administration has made the selection process more difficult and time-consuming.

Before the meeting with Jordan, White House press secretary Jody Powell was asked about an editorial in yesterday's editions of The Washington Post that criticized the slowness of the selection process.

"I can only say that the implication in the editorial may have been dated by a week or so," he said. "Our intention is to be careful and deliberate. It is our belief that the American people prefer us to be thorough rather than hasty."