White House spokesman Dan Howard said yesterday that President Reagan has made no decision about a replacement for Kenneth L. Adelman, the Arms Control and Disarmament Agency who resigned.

Howard and other White House officials denied a Washington Times report that Reagan has decided to name special U.S. arms adviser Paul H. Nitze to the job. One official who asked not to be quoted by name said the report appeared to be an effort by opponents of Nitze's nomination to generate a reaction against him on the part of conservatives.

Official sources said Nitze, 80, is one of several candidates for the job. The sources said others still under consideration include retired lieutenant general Edward L. Rowny, who is also a special U.S. arms adviser, and Ronald F. Lehman, chief U.S. negotiator for strategic arms at the U.S.-Soviet talks in Geneva and a former staff member of the National Security Council.

Retired lieutenant general Brent Scowcroft, who was national security adviser to President Gerald R. Ford, has also been mentioned as a potential director of ACDA, but Scowcroft said he is not interested.

The director of the arms control agency has been much less powerful than the secretaries of state or defense in setting policy for negotiations with the Soviet Union. But the ACDA head has a seat at most top-level meetings on arms policy, as do both Nitze and Rowny. Should Nitze or Rowny get the job, it is believed they would continue as presidential advisers even while serving as ACDA director.