BEIJING, JUNE 3 -- China's acting Communist Party chief and premier, Zhao Ziyang, left today for a visit to five East European countries that "will mark a new era" in China's ties with some of Moscow's closest allies, the official New China News Agency reported.

At an airport press conference, Zhao, who will be going to Poland, East Germany, Czechoslovakia, Hungary and Bulgaria during his 18-day tour, expressed satisfaction with the restoration of party-to-party ties between China and the five countries in recent years.

He also said he hoped to "see more of what the people of the five countries have achieved in their economic construction and reforms." Hungary and Poland, in particular, have pioneered economic and, to a lesser extent, political reforms within the Soviet Bloc.

Zhao, who became the party's acting general secretary in January while continuing in the premiership he has held since 1980, acknowledged that he has "an overload of work" in handling both of China's two top formal leadership roles under paramount leader Deng Xiaoping. He said that this fall's party congress would select someone "to take over one of my positions."

Asked which of his jobs he would prefer to retain, Zhao replied, "I feel that the position of premier is more suitable, not the position of general secretary," repeating his open preference for the government post. He said the decision was not in his hands, however, but would be made by the new Central Committee elected at the party congress.

Although most analysts believe Zhao is going to be selected for the higher ranking Communist Party post, his answer was carefully worded to avoid appearing overconfident, analysts said. Overconfidence was a factor that led to the downfall of former party chief Hu Yaobang in January, they said.

Zhao's visit to the five East European countries, described by the official Chinese news agency as one of "great political significance," is the climax in a series of exchanges begun a few years ago that have brought about a dramatic improvement in relations. China's ties with East Europe had chilled after the Sino-Soviet ideological and political split of the early 1960s.

Trade between China and the five countries reached $2.78 billion last year, but the figure is unlikely to exceed $2.58 billion this year, Chinese officials said. East European diplomats said this decline is due in part to China's efforts to put its economic house in order.

The visit of Polish leader Gen. Wojciech Jaruzelski last fall was the first by a leader of a close Soviet ally in more than 25 years. He was quickly followed by East German leader Erich Honecker. This year Czechoslovakian Premier Lubomir Strougal and Bulgarian leader Todor Zhivkov came to Beijing.

The Romanian party never broke relations with China, while nonaligned Yugoslavia's party restored ties following a 1977 visit here by President Tito.

The Chinese have repeatedly stressed that there is no linkage between improved ties with Eastern Europe and better ties with the Soviet Union. Indeed, some analysts see an incentive for Beijing to use improved ties with Soviet allies to pressure Moscow for concessions on what China calls the three main "obstacles" to closer Sino-Soviet relations. They are the Soviet occupation of Afghanistan, Soviet troops on China's borders and Moscow's support for Vietnam's occupation of Cambodia.

Nevertheless, East European diplomats said the visit is likely to improve understanding between Moscow and Beijing, especially since it follows so closely the annual meeting of the Warsaw Pact countries last week.

The two communist giants, said one Soviet Bloc diplomat, are like elephants. "It doesn't befit elephants to pirouette," he said. "But elephants are pretty good at learning how to dance."

In recent months, some diplomats said there have been some developments that may improve the atmosphere for normalizing Sino-Soviet relations.

On the main obstacle of Cambodia, for example, a joint Soviet-Vietnamese statement, issued last month during a visit to Moscow by Vietnamese party chief Nguyen Van Linh, appeared to recognize China's concerns.

According to a Tass report distributed by the Soviet Embassy here, the statement said a search for a political solution to the Cambodian problem "should be conducted with regard for realities in the region and with the involvement . . . of all sides concerned."

Said one analyst: "That message was clearly aimed at China."