The Supreme Court yesterday declined to review the payroll-kickback conviction of Rep. Charles Diggs (D-Mich.), who now faces a three-year prison term.

Diggs, who has announced his retirement from Congress as of next January, said he will seek a reduction of his sentence.

The justices let stand the conviction without comment. Diggs was convicted of 11 counts of mail fraud and 18 counts of falsifying congressional payroll forms.

Prosecutors said Diggs received about $66,000 in kickbacks from 1973 to 1977 by inflating the salaries of several staff members and by having them use portions of those salaries to pay his personal business and congressional expenses.

In other actions yesterday:

The justices ruled 8 to 0 that the Virginia Supreme Court does not have to pay attorney fees incurred by the Consumers Union of the United States in its successful suit against the Virginia court's ban on lawyer advertising.

The Virginia court was acting within its rule-making authority when it promulgated the now invalid ban on advertising that was challenged by the consumers group, the justices said yesterday, and is thus immune from suits for attorneys fees or money damages.

The state court would be liable if it violated civil rights in enforcing the rules, however, the Supreme Court ruled.Justice Byron R. White wrote the opinion, in which Justice Lewis F. Powell Jr. did not participate.

The Supreme Court also denied attorney fees to the Black Panther party, which sought the money in connection with a suit filed following a 1969 Chicago police raid on its headquarters. Two Panther leaders, one of them Fred Hampton, were killed in the raid.

The suit -- one of the longest running cases on record -- produced an appeals court ruling entitling the Panthers to a full trial on their charges. After that victory, Hampton's widow won an award of attorney fees.

The justices said yesterday that an award of attorney fees, should one be made, must await the outcome of the trial. An award before the conclusion is improper, they ruled.

The justices refused to halt California's investigation into alleged fraud by leaders of the Worldwide Church of God.

The Church and its leaders, who had alleged that their religious freedom was being abridged, now must comply with state court orders to surrender documents regarding the $70 million in donations the church receives each year.

California officials allege that church leaders have diverted and siphoned off money for their personal enrichment. The church is led by 87-year-old Herbert W. Armstrong, and has been embroiled in a highly publicized controversy over its finances.

The court refused a request by Hustler magazines owner Larry Flynt to delay paying a $27,500 fine for his obscenity convictions in Atlanta last year.

Flynt was convicted in 1979 after he personally sold copies of his sexually explicit magazines, Hustler and Chic, during a pornography crackdown in Georgia.

Flynt sought postponement of the fine pending a review of his appeal.