Treasury Secretary G. William Miller, warning that hasty action "for political reasons" could threaten the nation's economic progress, yesterday took a hard stand against a tax cut of any kind this year.

Miller, appearing on "Issues and Answers" (ABC, WJLA), said President Carter is prepared to consider "a carefully designed and carefully constructed tax cut done at the right time," but that the right time is next year, "outside the heat of the election campaign."

Miller's comments follow a flurry of activity on Capitol Hill that the White House fears may lead to passage of a preelection tax-cut bill.

After Republican presidential candidate Ronald Reagan formally called last week for a $36 billion tax cut, Senate Democrats deserted President Carter's stand on fiscal restraint and promised to unveil a tax-cut package of their own by Sept. 3.

Hoping to regain some control over the new tax-cut drive and to keep panicked Democrats from supporting tax reductions just to wrest the tax-cut issue from Republicans in an election year, the White House Friday agreed to work jointly with House and Senate Democrats to develop a party-wide strategy before mid-July.

The Carter administration has long contemplated a tax cut, Miller said, but not until after 1980.

The administration wants a tax-cut program tailored to meet specific objectives for revitalizing the American economy, Miller said, "but it should not be done for political reasons; it should not be done to mislead the American people and to try to buy their votes with election-year gimmicks."

Miller agreed with Senate Democrats who called Reagan's proposal for a 10 percent across-the-board tax cut "irresponsible and misleading and inflationary."

Citing the fall of interest rates and the inflation rate since March, Miller said, "We must not lose those gains; we must not throw them away through some hasty, hip-shooting action."

If through "loose talk and abandoning our discipline" inflation is revived, he said, "it will have been a tremendous hoax on the American people. Our policy on this will remain firm."

"I think Americans understand this," he said. "I think really they're too smart to fall for the Barnum and Bailey type of tax policy proposed by Gov. Reagan."

Miller declined to say that President Carter would veto any measure that came to his desk, but he dismissed the likelihood that Congress could produce an acceptable measure in the remaining legislative time.

"I think it's unlikely that a well-constructed tax program can be developed by Congress for action this year, but if a miracle happens, and a good sound program the president proposes and wants is done, we can accept miracles."

Miller said Carter has made no decisions on a tax-cut plan and that the president's chief economic advisers have made no recommendations to him yet.

On the economy, Miller said unemployment probably will be higher in the fourth quarter and predicted that the inflation rate will fall to below 10 percent by the end of the year. He said housing was beginning to show a base for recovery later in the year, and that the decline in auto production may have bottomed out.

In a separate interview, Philip Caldwell, chairman of Ford Motor Co., complained that the number of cars being imported from Japan is "out of balance" and needs to be cut back, although not necessarily by import quotas. Ford will "probably" lose money this year. Caldwell said on "Meet the Press," (NBC, WRC), although he added "we will start to work our way back" in the fourth quarter.

In other economic news yesterday:

The Conference Board reported that its help-wanted advertising index fell again in May for the sixth month in a row. The group's index, designed to be a barometer of changes in the demand for labor as well as general business conditions, measures the volume of classified advertising in 51 major newspapers across the country. Since October 1979, want-ad volume fell almost 33 percent nationally.

The nation's purchasing managers said in their latest report that new orders were down dramatically in June. Almost three-fifths of the 225 members of the National Association of Purchasing Management surveyed reported a decline in new orders.