KAHALUU, Hawaii (AP) _ An authentic Okinawan village, complete with Shinto shrine, thatched cottages and fields of rice, turnips, tomatoes and cabbages, has arisen on the lush, windward side of Oahu.

The setting is magnificent: A curving shoreline overlooks what is said to have been the royal fishing pond of King Kamehameha III. It is now owned by a Honolulu doctor. Beyond is the limitless blue of the Pacific Ocean.

It is the film location for Columbia Pictures' ''Karate Kid II,'' a sequel to Hollywood's biggest sleeper of 1984.

''The Karate Kid'' surprised almost everyone by amassing a domestic gross of $100 million. That's phenomenal for a modest film with no stars and a title that sounded like a combination of Bruce Lee and a kidflick. The movie business being as it is, a sequel was inevitable. In fact, producer Jerry Weintraub started plans in June 1984, as the first box-office returns started coming in.

The other day, he was casting an overseer's eye as John Avildsen directed a scene in which Miyagi (Noriyuki ''Pat'' Morita), who has returned to his roots after a 40-year absence, and his protege, Daniel (Ralph Macchio), are besieged by three young Okinawan toughs.

In Okinawans, led by California actor Yuji Okumoto, try to taunt Miyagi into a fight. They tear up a vegetable patch, hoping the karate master will become infuriated. Instead, he merely begins replanting the plants, joined by Daniel and peasant farmers. The toughs speed off in a sports car.

All this was meticulously choreographed by Avildsen, who studied a video screen that duplicated what was being photographed. The fight scenes, which will be filmed in Burbank, Calif., will also be as carefully planned as a classic ballet. Every move will be scripted, then rehearsed in slow motion until nothing is left to chance. Macchio will portray himself in closeups, but most of the fast action will be performed by a double.

''The Karate Kid'' cost a modest $9 million. The new film will run $14 million. The difference is partly in the sets: the Okinawan village here and a Naha street scene and an ancient castle, site of the final battle, at the Burbank Studios.

''The difference in costs between the two pictures is also because everyone's salary went up,'' said the producer, adding cheerfully, ''including my own.''

Between takes, Avildsen made a wry comment about what ''The Karate Kid'' had done for him: ''I started getting calls again. Before that, I was thinking of having the phone taken out.''

Avildsen had known some dry years between ''Rocky'' and ''The Karate Kid.'' He had accepted such films as ''W.W. and the Dixie Dance Kings'' and ''The Formula,'' but rejected ''Kramer vs. Kramer,'' ''The China Syndrome'' and ''Serpico.''

''I'm always suspicious of people who say they have no regrets,'' he remarked. ''I do. I also turned down 'Rocky II' because I didn't feel the character could suddenly become so dumb. Now I wish I had done it.''

The director came to ''The Karate Kid'' with no knowledge of martial arts. ''But I had great help from Pat Johnson, who choreographed the fights, and Bob Kamen, who wrote both scripts, is himself an expert who has a black belt.''

Avildsen had no hesitancy about directing the sequel. He was influenced by ''the continuing relation of the man and the boy who inspire courage in each other.''

Before ''Karate Kid II,'' Ralph Macchio was known principally for the TV series ''Eight Is Enough.'' According to Weintraub, the 24-year-old actor underwent training to build up his physique, but he still looks like an undernourished teen-ager.

Pat Morita was the major winner of ''The Karate Kid.'' The former nightclub and TV comedian won an Academy Award nomination for supporting actor. ''My bills got paid, my kids' education was partially provided for and now my wife says she loves me in public,'' he said. ''No, I shouldn't say that.''