Police Wednesday night raided four of the multiracial nightclubs that have been burgeoning in this city in defiance of South Africa's policy against racial mingling.

Officials have generally ignored the clubs which began sprouting here about a year ago. Club operators say they have been occasionally subjected to a "friendly" raid in which their liquor was confiscated, but for the most part they have been left alone.

Wednesday night, however, 12 arrests were made and police charged that the clubs were violating South African liquor laws.

Col. Piet Delport, head of the Johannesburg police department's vice squad, said the raids were not directed at multiracialism.

"Those arrested have been charged with dealing in liquor illegally or obtaining it on unauthorized premises," he told Reuter news agency.

Nevertheless, the crackdown follows a critical three-part series of articles on the club in the Afrikaans newspaper, Die Vaderland.

The newspaper account said at one point: "White and black mixed freely, often cudding, embracing and kissing each other publicly . . . Single men were solicited by black women using the line: 'Buy me a drink darling.' . . . No distinction was made between the races where toilets' were concerned . . . And not one of the clubs had a permit to admit people of nonwhite communities."

The paper also said that many policemen visited the clubs, "but not for purposes of enforcing the law" and that a department investigation was under way to see if some officers should be reprimanded.

During Wednesday's raids white male customers clambered over each other in an attempt to get out the front door of one club, Las Vegas, according to news reports. Detectives took down most of their names.

By accident, the most popular interracial club, jamed New York City, happened to be closed and was not hit by the raiders.

The clubs appeared to take the police action in strike. One Johannesburg reporter wrote that "20 minutes after the raid on the Las Vegas - during which all liquor was confiscated - all four bars were selling drinks brought in from a secret store."