Private athletic foundations at George Mason University in Fairfax and at the College of William and Mary in Williamsburg have been tardy in making payments owed to the institutions, according to reports by State Auditor Charles K. Trible.

The special reviews conducted by Trible's office followed suggestions by Attorney General Gerald Baliles that such foundations, which many state colleges and universities use as private sources of financial support, face "little, if any, accountability for the raising and spending of millions of dollars . . . "

Trible's reports, released in Richmond, shows that The Patriot Club of George Mason Foundation Inc. was more than $124,000 in arrears with payments to the school as of June 30, 1981. The total was about a third of the amount owed the university at the time, the report said, and $31,534 of the delinquent sum had been outstanding for a year.

A spokesman for GMU President George W. Johnson said steps were being taken to collect the money, used for athletic scholarships, on a timely basis so that by the 1983-84 fiscal year the money will arrive during the fiscal year in which it is used.

The problem at George Mason occurred when the school decided to elevate its athletic programs to Division I status three years ago, Johnson said in a statement.

At William and Mary, Trible's report said, $120,000 of a $150,000 loan made by the W&M Board of Visitors to the Athletic Educational Foundation of the College Inc. in June 1979 remained unpaid as of June 30, 1981, the end of the 12-month audit period.

Trible said he recently began paying closer attention to the finances of the college-related foundations because new auditing principles require him to review activities of affiliated, private organizations.

Baliles has announced a detailed investigation of all college foundation activities in response to still-unspecified "legal problems."