Vice Chairman Deng Xiaoping has offered to step into semiretirement this year as part of a deal to remove his conservative opponents from active leadership roles, according to informed Chinese sources and foreign diplomats.

Deng, 77, the prime mover in China's current reform era, has proposed that he and other aged Communist leaders give up their party posts and form an advisory committee to supervise policy-making activities of the Politburo, the sources said.

If the plan succeeds, Deng is still expected to have the dominant voice in Chinese political life through the proteges he has managed to place in key party and government jobs, including party Chairman Hu Yaobang and Premier Zhao Ziyang.

At the same time, Deng would score a major victory in sidelining several old-line Politburo members who represent rallying points of opposition to his unorthodox strategy for modernizing China's economy and his outward-looking foreign policy.

"The whole idea is to get guys antithetical to Deng out of the way," said a Western diplomat. "If Deng becomes an adviser, he still calls the shots because he's got Hu and Zhao. If the conservatives move into that role, they'll get held to the letter of it."

The primary targets of this strategy are believed to be Vice Chairmen Li Xiannian and Ye Jianying, two conservative mainstays of the Communist hierarchy who have formed pockets of resistance to Deng at various stages of his consolidation of power since 1978.

Li, 72, a senior economic specialist, heads a faction of Stalinist planners who favor a heavy industry orientation to development rather than Deng's emphasis on light industry, moderate growth rates, material incentives and use of market forces.

Ye, 85, a Red Army marshal and former defense minister who is China's most influential military figure, is believed to have opposed Deng's sharp criticism of the late party chairman Mao Tse-tung and the junking of Mao's radical precepts on guerrilla war and social equality.

Li and Ye flourished during the Cultural Revolution of 1966 to 1976, during which wide-ranging purges ousted Deng and other party officials who swept back into power in 1978. They also are said to have backed former chairman Hua Guofeng, Mao's hand-picked successor, who lost out to Deng in a power struggle last year.

Conservative followers of Li and Ye are believed to be critical of Deng's conciliatory moves to reunify Taiwan. With Washington unwilling to set a deadline for halting arms sales to the breakway island, they also are said to be questioning Deng's tilt to the United States in world affairs.

Although Li and Ye have publicly supported the ongoing campaign to rid the bureaucracy of elderly officials, it is unclear if they would be willing to step aside themselves at the party congress scheduled for later this year and form an advisory group with Deng.

Since Deng's offer to resign is believed to be tied to the willingness of his opponents to join him in the advisory panel, sources caution that the whole deal could fall through if officials refuse to cooperate.

Deng has deftly maneuvered to edge out most Maoists from leadership ranks, installing instead officials cut in his own mold--pragmatic modernizers. The current bureaucratic housecleaning is designed to achieve the same goal at lower levels.

Two of Deng's closest allies--Wan Li and Yao Yilin--were the only two vice premiers reappointed earlier this month. The naming of 13 new party department chiefs two weeks ago elevated a further batch of officials associated with Deng and Hu.

Although Deng has rearranged the government and party apparatus to his liking, he has yet to put his stamp on the nation's supreme political body--the Politburo--which was elected in 1977 when China had not completely shaken off the effects of the Cultural Revolution.

Deng hopes to complete his remarkably smooth transition of power when the upcoming party congress elects a new Central Committee and Politburo, Chinese sources say. He is said to want a younger body committed to his policies.

Seeking to "set an example" for other elderly Communists, Deng has agreed to step down, and he has floated a draft of a new party charter with provisions for a top-level advisory board that would function alongside the Politburo, an Asian diplomat said.

The diplomat, who has been briefed by Chinese officials, said the advisory panel would have as many as 50 members, serving as a catchall for elderly leaders of all political persuasions--although the effect would be to dilute conservative power.

"Basically, it's a brilliant strategy to get rid of Deng's elderly opponents," he explained. "If Deng agrees to retire and join the committee, how can the others refuse?"

The idea of an advisory panel to supervise the Politburo was first raised by Deng in an important August 1980 speech outlining the organizational reforms that have since taken place to enhance the power of moderates within the ruling circle.

Deng vanished from public view for five weeks early this year amid official reports that he had withdrawn from day-to-day decision-making to give his designated successors, Hu and Zhao, a full opportunity to run China without his overshadowing presence.

Since resurfacing Feb. 18, Deng has again occupied center stage in Chinese politics, appearing publicly at least once weekly and receiving important foreign visitors, including Vice President Bush. Chinese sources say he has the final word on all national issues.

If Deng relinquishes his party post, it is unclear if he also will give up other official positions, including his chairmanship of the party's Military Affairs Commission.

Observers also remain unclear how Deng's plans will influence the selection of two new posts provided in China's proposed constitution--head of state and chairman of a new central military council that is to be responsible to the national parliament, not the party.

Ye, who is chairman of the parliament, has acted as de facto head of state in recent years. But his advanced age and fragile health have greatly reduced his activities, and he told Hong Kong journalists May 1 that he plans to step into an advisory role.

But Ye's remarks, which did not specify from which posts he would retire, have never been published in the mainland press.