Health and Human Services Secretary Margaret M. Heckler, under strong pressure from White House officials, is expected to leave the Cabinet to become ambassador to Ireland, but President Reagan has not given final approval to the shift, presidential aides said yesterday.

The officials said they expected Heckler to leave the Cabinet, and one said the president "is not blind" to criticism of her. But they added that Reagan had yet to personally agree to move Heckler out, as has been sought by White House chief of staff Donald T. Regan.

Officials said Reagan will probably meet with Hecker soon about her future.

When the possibility of the ambassadorship to Ireland arose in August, Heckler said, "That's a lovely position for somebody else."

Heckler yesterday was fighting to keep her current job. A list of "talking points" on why she should not be ousted has been circulated on Capitol Hill, and key lawmakers have phoned Regan to express support for Heckler.

At the White House, presidential spokesman Larry Speakes said a Washington Times report that a final decision had already been made by the president to force Heckler to shift to the job of ambassador to Ireland was "incorrect."

"She remains as the secretary of HHS and there have been no discussions at the top level of the White House . . . meaning the president or Regan, with her, about any change in her position," Speakes said.

He added, "The president has been pleased with her job performance."

Heckler also got a strong expression of public support yesterday from Senate Labor Committee Chairman Orrin G. Hatch (R-Utah). "I think she has done a terrific job," Hatch said, adding he is "outraged" by attacks on her performance and administrative abilities by "White House leakers."

For months there have been reports from the White House, which the president has repeatedly denied, that Heckler would be replaced by former undersecretary John A. Svahn or former undersecretary David A. Swoap.

Regan has been highly critical of her performance and has indicated to White House colleagues that he would be pleased if she would resign and shift to an ambassadorship.

The key question is whether the president, who has often been reluctant to fire his own appointees, has given Regan a go-ahead to force Heckler out. "If Regan had a strong hand and a go-ahead from the president, he would have called her in yesterday and fired her," said one Heckler supporter.