A Tokyo district court today handed down suspended prison sentences to two veteran Japanese politicians for their roles in the six-year-old Lockheed bribery scandald amid a renewed speculation here about the fates of key Liberal Democratic Party powerbrokers.

In separate court proceedings, former prime minister Kakuei Tanaka is accused of accepting a $2.1 million bribe for allegedly using his influence to promote the sales in Japan of Lockheed TriStar passenger jets.

Today's court ruling, the first involving national political figures in the Lockheed affair, has been widely interpreted here as a sharp blow to the former prime minister's own court defense and his vast political influence.

In handing down the decision, Judge Kazunobu Araya found Tomisaburo Hashimoto, 81, a former minister of transport, and Takayuki Sato, 54, a member of parliament from the ruling Liberal Democratic Party, guilty on charges of having accepted a total of $30,000 in bribes from All-Nippon Airways, Japan's largest domestic airline, in return for political favors. The money allegedly was handed over to the two men by executives of Marubeni, the Japanese trading company that acted as Lockheed's agent for aircraft sales in Japan.

Araya sentenced Hashimoto, a close political ally of Tanaka, to two and one-half years in prison and Sato to a jail term of two years, but suspended the sentences pending a three-year probation for each man. The two men were forced to give up formal membership in the ruling Liberal Democratic Party following their indictments in the Lockheed case.

Prosecutors alleged that the two men, both veteran Liberal Democrats appointed to key political posts in the transport ministry in the early 1970s, used their influence to stall government approval of plans by Japan Air Lines, an All-Nippon Airways rival, to introduce wide-body jets on its domestic routes. The delay, prosecutors said, gave ANA some much needed breathing space to mount its own ambitious program of fleet expansion. ANA subsequently purchased 18 Lockheed Tristar jets for that purpose.

The outcome of the trial, one of three put in motion by the 1976 scandal, is important because, although it did not directly involving Tanaka, prosecutors alleged that the ex-premier received an additional $42,000 in "thank you" fees from ANA in return for political favors.

Prosecutors also linked current Liberal Democratic Party Secretary General Susumu Nikaido and three other prominent party members to alleged ANA payoffs. These so-called "gray officials," seven in all, allegedly netted $125,000 for influence-peddling on ANA's behalf.

Tanaka has remained confident of an acquittal, although the recent string of convictions in the case represents a serious setback for the tough politician. Should the verdict--now expected some time late next year--go against Tanaka, his lawyers have indicated they would undertake a lengthy appeal.

A guilty verdict could force Tanaka's departure from national politics and have a destabilizing impact on the Liberal Democrats, who have run government here for the past 27 years, analysts said. It is still too early to tell, but a wholesale grab for power, could risk the ultimate breakup of the party, they suggested.

Today's verdicts were expected to touch off a political tempest. Opposition party leaders in the Japanese Diet today issued a hotly worded statement calling for Sato to resign his Diet seat (Hashimoto left the Diet two years ago after an unsuccessful re-election bid).

The air of expectation surrounding today's rulings grabbed public attention here and overshadowed Prime Minister Zenko Suzuki's current diplomatic tour, including his participation in the Versailles economic summit last weekend and a stopover in the United States this week.