If President Carter decides that he has to take drastic steps to try to shore up the value of the dollar, he has an arsenal of sweeping emergency powers that he could draw on.

But administration officials, who admit to "deepened concern" about the continuing slide in the U.S. currency, say that most of the steps President Carter could take would do little to change the situation.

Other moves, such as slapping restrictions on imports, might reduce the size of the trade deficit, temporarily but in the long run would worsen international trade relationships.

Top presidential advisers such as Tresury Secretary W. Michael Blumenthal and Federal Reserve Board chairman G. William Miller have, warned speculators for several months that the administration could take further steps to try to halt the dollar's slide. But they decline to say what those steps might be to try to keep international money speculators off balance.

The steps the administration has taken so far do not have the arshness of the emergency powers the president has under the International Emergency Economic Powers Act, passed last December.

If the president declared an international economic emergency - a an action which must follow specific procedures and one which could be overturned by Congress - he would have almost total control over all international transactions an by an American business, bank or citizen.

"It gives him complete regulatory power with respect to any transaction," observed one congressional official.

If the president declared an emergency on the international economic front he could, among other things:

Limit or prohibit the amount of dollars that citizens or businesses could use to buy foreign currencies.

Stop individual or businesses from investing abroad.

Restrict international lending.

Control the amount of exports permitted into the United States.

Assistant Secretary of Commerce Frank Weil noted however, that most of the emergency powers the president has would do little good in the current dollar crisis because American citizens are not deserting the dollar.

The dollar's decline is directly traceable instead to foreigners, who hold about 500 billion dollars and are selling them rather than buying, investing or saving them.

Although the president can stop an American bank or individual from selling dollars (or buying them, for that matter), he cannot do anything to stop a Swiss national from selling dollars in Zurich.

The size of the U.S. trade deficit - about $28 billion last year and expected to be as big or bigger this year - is commonly cited as a big factor in the dollar's decline.

By importing many more goods than it sells abroad, the nation is increasing the supply of dollars in a world that already has more dollars than it wants.

The president could act to reduce that deficit by slapping controls of imports.

But one official noted that whatever short-run gains import controls might buy would be more than offset by the restrictions foreign government would likely slap on American goods in retaliation.

Furthermore, such a unilateral action by the U.S. would likely doom completion in Geneva. Those talks are aimed at liberalizing international trade.

What the president has node so far to try to stem the slide in the dollar does not impinge on the freedom to make economic transactions as would his emergency powers.

So far the administration and the Federal Reserve Board have:

Raised domestic interest rate to encourage foreigners to invest here and to encourage domestic borrowers to soak up some foreign dollars by getting loans abroad.

Changed regulations on domestic banks to encourage them to borrow dollars from their foreign branches.

Sharply increased the amount of gold the Treasury auctions each month, both to reduce the trade deficit and, implicitly, to reduce thevalue of gold that is bought and sold internationally.