TOKYO (AP) _ Opposition parties said Monday that local elections show voters want Prime Minister Noboru Takeshita's government to quit, but the ruling party said political reform would win back the people's confidence.

Chief government spokesman Keizo Obuchi dismissed opposition calls for general elections, saying Sunday's ballot ''was a gubernatorial election to select the governor and not a referendum.''

The ruling Liberal Democratic Party candidate narrowly defeated a communist contender to win the governorship of Chiba province neighboring Tokyo.

Newspapers said Monday the result showed waning support for the party, which is embroiled in an insider trading scandal. Its bruised image suffered more when it pushed an unwelcome 3 percent sales tax through parliament in December. Together, they have driven Takeshita's popularity to a record 15 percent low, according to Asahi Shimbun, Japan's second largest newspaper.

Three Cabinet ministers have resigned and 12 bureaucrats and businessman have been arrested in the stock-profiteering scandal involving Recruit Co.

Takeshita has refused to call new elections. But elections are scheduled in July for half of the bicameral Parliament's House of Councilors, where Liberal Democrats hold 143 of the 251 seats.

Large losses there would endanger Takeshita's chances in October to win another two-year term as party president and prime minister.

''From now on, our party will promote political reform and strive to revive the confidence of the people in government,'' said Shintaro Abe, secretary- general of the ruling party, following Sunday's vote.

He called Takeshi Numata's narrow victory a positive sign residents were prepared to support the party despite the scandal.

But the opposition noted Numata defeated communist Shoji Ishii by only 971,687 votes to 786,238 votes, compared with a 1985 victory of 781,000 votes to 271,000 votes over another communist candidate.

In a second gubernatorial race Sunday, for Miyagi prefecture, Socialist Shuntaro Honma easily won with 502,372 votes. His nearest rival was conservative independent Seiki Suzuki, with 140,979 votes.

Liberal Democratic candidate Kazuo Aichi had withdrawn earlier after admitting he received more than $60,000 from Recruit, the information conglomerate also accused of bribing legislators in a bid to bury the scandal.

Recruit offered bargain-priced unlisted stock in a subsidiary to more than 150 influential politicians and businessmen in 1986. Recipients made handsome profits once public trading in the shares began later that year.

Calling for new national elections, Socialist Party opposition leader Tsuruo Yamaguchi said, ''The election results are substantiated by the latest public polls by the media and clearly show that the Takeshita Cabinet has lost its ability to govern.''

The Communist Party said: ''The people are united ... in calling for the early dissolution of the Takeshita Cabinet and the holding of a general election.''

Japan's biggest newspaper, the conservative Yomiuri Shimbun, commented, ''In Chiba in particular, where the number of votes obtained by the communists grew substantially, voters distinctly showed their irritation and rage regarding the Recruit problem.''

The ruling party also was stung last month when it lost a parliamentary by- election in Fukuoka prefecture to a candidate supported by its biggest rival, the Socialists.

The Liberal Democrats have ruled Japan since World War II with the exception of 10 months of Socialist government in 1947-48.