A television consultant to the Taiwan government's official Chinese information Service says an incorrect entry appeared in his filing of activities with the U.S. Justice Department. The incorrect filing said he had bought lunch in April, 1975, for Reuven Frank, producer of NBC-TV' Weekend show. The filing was reported in the June 9 Washington Post. Actually, Alan Prigge, the consultant, said yesterday, the entry should have been for someone else.

Miss Lillian was there, was most of the city council. It was, all in all, as the mayor's wife said, "a pretty nice time" Monday when the eight or so visitors from Kaohsiung, Taiwan (population 1 million), gave Plains, Ga. (pop. 700), $25,000 for an oriental garden right there in the middle of the President's hometown.

Plains and Kaohsiung have become sister cities, and for the obvious reason. "I'm sure it was political," said Mayor Boze Godwin. "We have nothing to give in return."

The ceremony and the park, and the free April trip of four Plains officials to Kaohsiung to plant peanuts in a park, were all part of the official and unofficial Taiwan forget-me-nots sent to the American public each year.

Documents on file with the Justice Department show that the Taiwan government spent some $1.4 million on public and business relations in the United States last year. The official Chinese Information service has more than doubled its annual spending here - from $504,524 to $1,028,263 - since Taiwan was voted out of the United Nations in 1972 in favor of mainland China.

The service, which says it assists those doing research on China, has bought a $14.38 bottle of Christmas champagne for New York Times columnist William Safire, as well as a lunch and dinner for him. Alan Prigge, the service's $1,000-a-month television consultant, has placed Chinese officials on ABC-TV and NBC-TV programs - and hosted the producers Jim Hill and Reuven Frank, at lunch.

And last year, Taiwan signed a $225,000 contract with New York public relations man Sidney S. Baron, who says his work is mostly with businessmen and trade shows. Among other things, his New York firm has gotten a gubernatorial proclamation honoring a science and industry exhibit and a TV appearance for a visiting dignitary. The contract for this year is for $275,000.

"They are obviously interested in investment," Baron said in an interview. "Having good eocnomic relations is a source of security."

If trade is security, then the Taiwanese have done well despite former President Nixon's ending of the United States' hostile relationship with mainland China. In 1971, trade between the United States and Taiwan totaled $898 million, according to the Chinese information Service. Last year it was $4.8 billion.

But it is unknown security at a time of announced intentions by the Carter administration to normalize relations with a number of countries - even mainland China, if the delicate issue of U.S.-Taiwan relations can be resolved.

So in addition to the official and overt efforts by the Taiwan government to make fast friends in the United States, there are the unofficial sister-city and other programs of Chinese residents and Taiwan backers here.

It was a prominent Chinese professor in California who, by all accounts, dreamed up the Plains-Kaohsiung connection after the November election. Mayor Godwin said Kaohsiung paid the expenses of the Chinese trip for the four Plains representatives, including himself. "We couldn't have paid for one," he said.

And while the mayor of Portland, Ore., was visiting Peking recently, members of the City Council sent a letter to President Carter urging a continuation of diplomatic relations and mutual defense treaty with Taiwan. The letter was circulated by a city commissioner who has received support from Portland's active Chinese community.

There have also been other ways of winning friends and influencing the right people. Last year, it was revealed that dozens of members of Congress and congressional aides had been treated to all-expense-paid trips to Taiwan and South Korea.

The Pacific Cultural Foundation in Taipei, whose source of funds was unclear, paid for the Taiwan trips, but an embassy spokesman said here yesterday that there have been no junkets since the disclosures.

So what does all this get?

For the oriental garden in Plains, apparently not much.

"You could gather from reading the newspapers - you could pretty well tell" what was on their minds about mainland China, May or Godwin recalled of his trip. "We were very sympathetic to them. But we can't involve Mr. Carter in any way."