Administration officials said yesterday that they have detected a "slight softening" in Soviet statements since Foreign Minister Andrei A. Gromyko met with President Reagan last week, noting that Moscow has not directed sharp blasts at Reagan since then.

"We've had a good feeling ever since they called for the . . . meeting" between Gromyko and Secretary of State George P. Shultz, said a White House official who asked not to be identified. Those two met the day after Gromyko visited Reagan.

A second official said, "They are going to have to find a way to change their line."

Reagan campaign strategists have made no secret of their hope for a sign of warming U.S.-Soviet ties before the election Nov. 6.

In a statement in Moscow Thursday, the Soviet Politburo said that the Soviet Union is ready for a "serious, businesslike dialogue" with the United States and that Gromyko's meetings were "important and useful."

But the statement also said Gromyko did not detect in either meeting any sign that the United States intends to "adjust its policy course toward realism and peacefulness."

"We have taken note of the Politburo's statement that Foreign Minister Gromyko's meetings were important and useful," White House spokesman Larry Speakes said yesterday in response. "We agree with that description," he said.

"We hope the meetings will pave the way for a more productive dialogue with the Soviet Union and agreement on practical steps to improve our bilateral relations," Speakes said.