China stepped back from a confrontation with the United States by saying today that conventionally powered U.S. Navy ships may call at a Chinese port but not mentioning whether the vessels could carry nuclear arms.

A two-sentence statement dated Sunday but released through the Chinese Embassy here today seemed aimed at giving the United States and China more room to maneuver out of a potential confrontation over whether U.S. warships would be carrying nuclear weapons on a planned port call to Shanghai this spring.

The Chinese statement said, in effect, that China is in control of the type of ships that enter Chinese waters. But it left open the possibility of a port call by conventionally powered but nuclear-armed U.S. ships this spring.

This marked a step back from statements made in an interview last week in Peking by Communist Party chief Hu Yaobang and a high-ranking Chinese Foreign Ministry official that seemed to indicate that China was ruling out the possibility of any nuclear-armed ships participating in the port call. The Chinese officials made the remarks before Hu left for a five-day visit here.

The Chinese seemed to be trying to head off any confusion that might develop from questions put to Hu at a press conference scheduled to be held here Tuesday. The U.S. refusal to provide explicit assurances on this question to Australia, New Zealand and Japan has provoked political controversies in those countries and recently prompted New Zealand to ban U.S. warships from making port calls unless the United States confirmed that the vessels were not carrying nuclear arms.

The Chinese statement today said: "U.S. conventionally powered naval vessels may call at a Chinese port on an informal, ceremonial visit. This is a matter solely between China and the United States, and there are questions remaining to be settled between the two sides."

U.S. officials said last week that the remaining issues concerning a port visit were technical ones being negotiated by naval officers from the two sides and not policy questions, such as the type of weapons the ships would carry.

Last week, Washington said it had not changed its policy of neither confirming nor denying the presence of nuclear weapons aboard U.S. ships. The State Department since has said that the United States has given no assurances to China that nuclear-armed U.S. warships would not participate in a port call.

By saying that the anticipated port call would be informal and ceremonial, the Chinese seemed to play down the importance of the visit. It could take place in Shanghai as early as next month, according to some sources.

Meanwhile, although he holds no formal government position, Hu, the general secretary of the Chinese Communist Party, was being given treatment usually accorded to a head of government. Hu held talks here today with Prime Minister Robert Hawke and other government officials. The Australians greeted the visiting Chinese leader with a formal ceremony at Parliament House that included a 19-gun salute.

In a luncheon speech at Parliament House, Hu praised Australia for having "opened up a new world of wealth and prosperity in the vast wilderness." Hawke praised China's economic modernization program, saying that it was "releasing the initiative and enterprise of a dynamic people."

Hawke indicated that Australia will continue to seek to play a mediating role aimed at resolving the Cambodian conflict. In an obvious reference to Vietnam, he said that it constituted a risk to the region's achievements to have "an isolated country at loggerheads with the others and tied virtually exclusively to the Soviet Union and its allies."

In a briefing for reporters, an Australian official said later that Hu in his talks today with the Australians commented that China "fully understood the good intentions of Australia on Indochina" and "appreciated Australia's continued efforts for peace in Indochina and a peaceful settlement of the Cambodian question."