The Reagan administration said Friday despite "significant progress" by the Soviet Union in human rights, the United States is not ready to agree to a proposed human rights conference in Moscow.

State Department spokeswoman Phyllis Oakley said while hundreds of Soviet political and religious prisoners have been released the past two years, it is believed others are still held under trumped up criminal charges."They have made significant prog-ress . . . (yet) we continue to press for the resolution of all outstanding cases of political prisoners known to us," Oakley told a news conference.

The Soviet Union has proposed that Moscow be the site of one of three human rights conferences in Europe, which are to be held in accordance with the 1975 Helsinki accords.

Although some U.S. allies have urged support for the Moscow conference, the United States has set conditions for its acceptance, including demonstrable improvements in Soviet human rights performance and guarantees of access by groups and individuals that would attend such a meeting.

U.S. officials had hoped for a resolution of the matter by the end of this year.

The statement read to reporters Friday at the State Department by Oakley and in California, where President Reagan is vacationing, by White House spokesman Roman Popadiuk, is consistent with the view the administration has taken in recent months of the human rights situation in the Soviet Union.

While applauding the release of political prisoners and the relaxation of curbs on emigration the administration has continued to raise questions about specific cases.

It has consistently kept pressure on Soviet leader Mikhail Gorbachev to make good on promises of changes in the Soviet legal system to guarantee more freedom.