Vienna — Leaders in Hungary, with one eye on Moscow, are talking about taking on a ''multihued'' approach to communism. This approach, still very much in the talking stage, could eventually draw back Communist Party control of the nation's economy and modify government authority to allow more ''debates with partners of other convictions.''
There is intense discussion in Hungary on the need to open the door to genuine public participation in the decisionmaking process. But the discussion is not expected to raise eyebrows in the Soviet Union - Hungarian leaders find encouragement in the Kremlin succession of Yuri Andropov.
In fact, they were saying six months before the transition occurred in the Soviet leadership that Mr. Andropov was certain to be Leonid Brezhnev's successor.
Only two weeks after he became Soviet party chief last November, Mr. Andropov told the Soviet party Central Committee that valuable economic lessons could be learned from ''fraternal countries.'' It was a clear enough allusion to the one East European state that has made a go of reform, and the Hungarians became more confident.
Andropov was Soviet ambassador to Hungary during the 1956 uprising, and Hungarians say he understood the subsequent radical departures from the way the Communist Party had been running the country.
Hungary already does rely quite a bit on the profit motive to run its economy. The ideas being discussed, some of the nation's economists say, would carry market forces to still more logical conclusions while leaving the Communist Party as guardian of the basic ''socialist'' essentials.
A second concept would enhance political pluralism by changing the old idea of ''democratic centralism'' of party management and government.
One of the advocates of these ideas is Rezso Nyers, a party committee member and a leading figure at the Economic Institute of the Hungarian Academy of Sciences. His sponsorship gives great weight to this new debate.
One of the principal creators of the 1968 reform as well as a former Politburo member and finance minister, Mr. Nyers was replaced when the 1970s world recession - and a general setback to East-bloc reform after Czechoslovakia - caused some back-pedaling in Hungary. He remained, however, a convinced advocate of more, not less, reform.
Recently, in the Budapest daily Magyar Hirlap, he came out strongly for a larger political role for the Parliament and opportunities for alternative opinions to be heard within it.
Parliament thus far, he said, had no more than a ratifying role and could pronounce on the general performance of government only after the fact.
Nyers, in effect, admits that under a one-party system, Parliament inevitably has a purely secondary role. But he says that can - and must - be improved by allowing diverse voices in higher legislation and a control function over the concrete activities of government departments.
Citing the economy as an example, he said: ''Reports by ministers every five years or submission to Parliament of five-year plans in final form are not enough. Choices between alternatives (would therefore) be needed.''
Nyers seems to be calling for new interpretations of past political methods to make way for the pluralism that the economic reform itself is creating in society.
That - he says cautiously - does not mean dispensing with ''democratic centralism.'' While a revolution is settling down, it is a necessity. But, Nyers says, it has to be applied differently in a stabilized, more advanced society where a single-party state must heed varying public needs.
Electoral ''reform'' has been mooted in Hungary for some time. But simply having multiple candidates, Nyers argues, will be of no avail if the ''content'' of parliamentary and local council work is not improved by the active participation of diverse interests.
''Alternative opinions'' exist, Nyers insisted in the Magyar Hirlap interview. That view is supported by party leader Janos Kadar, who has said criticism is not ''opposition'' nor is one who holds a contrary view ''an enemy.''
Writers also have taken up the participation issue with a ''right to know'' article in their union journal, Elet es Irodalom, challenging official censorship and suppression of news regarded as harmful or embarrassing to party aims.
It was confusing to people, one writer said, when they read nothing in their papers of events they are aware of. ''Truth will out finally,'' the paper said.
The question inevitably arises as to how far pluralism may be allowed to ride. Even the word is not used in the Western form. Nyers uses a Hungarian word for ''multi-hued,'' though his meaning, of course, is perfectly clear.
The party's ideological guru, Gyorgy Aczel, told a recent high-level conference on culture that all experience since 1956 had taught the party the necessity of ''debates with partners of other convictions.''
Those ''partners,'' he indicated, still do not include either dissidents or other opponents of Kadar-style ''consensus socialism.'' But he says the reform process continues.
Whatever the present difficulties - both economic and amid East-West tensions - greater, not less, democratization is needed to solve them, primarily, Mr. Aczel added, because livelier debate and ''new answers suited to today's new situation'' are needed.
Call it pluralism or ''multihued,'' liberalism seems to be the direction Hungary is heading. And it apparently is doing so with a paternal nod from its friend in the Kremlin. The mere fact of the debate is significant.