Supersensitive to criticism, the Reagan administration is trying to impose a total news blackout on the internal debate at top levels on whether or not --and in which directions--the president should modify his economic program so as to reduce the huge budget deficits that lie ahead.

Members of the president's economic advisory board--all Republicans, most of whom have served other Republican presidents--are cautioned not to "leak" what goes on in their meetings. Cabinet members involved with economic policy must be super-cautious in discussing the deteriorating economic situation and any mid-course policy "correction" that may be needed to meet it.

But the degree of concern among many inside the administration that the economy is heading for a big spill-- which, incidentally, could overtake the Republicans at the polls in November -- makes such a news blackout impossible.

Thus, one official whispered to an important businessman who had expressed his belief that the president must alter his program to bring down interest rates and restore business confidence:

"I wish you'd put that in a letter to the president, because none of us seems able to reach him."

The information available to this reporter suggests that among advisers who have personal contact with the president, only New York Rep. Jack Kemp has not urged him to take specific action to curb the budget deficits laid out in the program sent to Congress two months ago.

Even Treasury Secretary Donald T. Regan, who had been out front in defense of the Reagan program--berating his former business colleagues who have criticized the president--reportedly takes a different position in private internal councils.

But the president doesn't want to hear criticism of his economic program --especially the tax cut, which he regards as the central "mission" of Reaganomics--from officials, the press, or anyone else. As he told the National Association of Manufacturers in a speech the other day, he is sore at those in the business community calling for tax increases to cut the deficit. He much prefers the Milton Friedman view that higher taxes merely encourage the government to spend more money.

Reagan spurns further discussions that might flush out bad news or criticism of his economic program. Thus, after having met several times earlier this year with his "outside" economic advisory board, he disappointed members by not showing up for a scheduled meeting last Thursday.

It was just as well for the president's equanimity that he didn't attend. Except for economists Arthur Laffer and Friedman (who later said on "Meet the Press" that "contrary to the common opinion, I believe the president has achieved a great triumph"), most of the others focused on the need for a swift reduction of the prospective deficits, and some argued outright for action to raise tax revenue.

None of this goes down well at the White House, where a siege mentality is building up. Any crack in the unanimity of support of the president's program among his advisers, he is said to feel, reduces his ultimate ability to negotiate the best possible compromise with Congress.

Contrary to charges by some businessmen that he has shown himself to be inflexible, two well-informed sources say that Reagan has worked himself into "a brilliant negotiating position."

"It's too soon for the president to show his hand," says one who's played cards in the Washington political game before. "Anything he concedes before the Easter recess--well, he just won't get anything for it in exchange. He can use the mid-May debt ceiling extension bill to get what he wants from Congress.

"This is not a negotiation among gentlemanly players in an academic setting. It's not an intellectual meeting of the minds, but a straightaway political power struggle."

Reagan, according to one person close to the White House scene, is keeping key members of his own party, as well as the Democrats, so anxious to reduce the deficits that they will in the end support a reduction in Social Security entitlements. Only then might the president yield to key Democratic demands--a reduction or elimination of the third stage of the Kemp-Roth personal tax cut, and a cutback in the defense budget.