WASHINGTON (AP) _ Backing away from an upbeat assessment by the U.S. ambassador to Beijing, the State Department said Wednesday China's human rights performance falls far short of U.S. conditions for an extension of trade benefits.

U.S. policy on China was thrown into confusion last week when Ambassador J. Stapleton Roy told an interviewer that ''dramatic'' progress had been made in the protection of human rights in China.

The statement seemed at odds with State Department evaluations on the subject. On Wednesday, acting spokesman Christine Shelly said the department stands by recent comments by Secretary of State Warren Christopher that ''much more needs to be done.''

At issue is whether goods imported from China will continue to incur the lowest possible tariffs permitted by the United States. Last spring, President Clinton issued an executive order approving a one-year extension of these trade benefits but said significant improvements in China's rights record would be required for an additional extension in 1994.

Given the volume of China's trade with the United States, an increase in tariffs could have a substantial impact on imports from that country. Total 1993 U.S. imports from China were about $31 billion.

U.S. officials, asking not to be identified, said the rights issue will be taken up in the coming weeks during a yet-to-be-announced meeting between Christopher and China's Foreign Minister Qian Qichen. The meeting is expected to be held in either Europe or New York.

Clinton made China's rights record an issue in the 1992 election campaign, and the subject has been discussed repeatedly at high levels over the past year.

''We are using our dialogue with the Chinese ... to underscore the seriousness of our concerns about the human rights issue and the need for progress,'' Shelly said.

Another administration official, speaking privately, said there are a lot of mixed feelings over how much weight to give the rights issue in the debate over trade benefits for China. The official added there is sensitivity to concerns in the business community, which strongly opposes any restrictions on trade.

Shelly declined to mention specific concerns, but her general assessment was seconded by Mike Jedrzejczyk, the China specialist at Asia Watch, a private human rights group.

''There's been no substantial letup in the level of repression since the executive order was issued,'' he said in a telephone interview. ''In some cases conditions have deteriorated.

''Strictly interpreting the executive order, I don't see any way Clinton could renew (the trade benefits) right now without undermining his credibility both on Capitol Hill and Beijing.''

Jedrzejczyk said thousands of political and religious dissidents remain in jails, prisons and labor reform camps; arrests and trials are continuing in China and Tibet.

Rep. Chris Smith, R-N.J., said Tuesday following a visit to China that many in Congress will oppose renewal of trade preferences for China even if, as he suspects, Clinton decides to ''whitewash'' the Chinese human rights record,

Without major changes in the coming months, ''Mr. Clinton will have a problem saying substantial progress is being made,'' he added.