Maryland gubernatorial candidate Theodore G. Venetoulis charged yesterday that under the administration of his opponent, acting Gov. Blair Lee III, the state is paying nearly $100,000 more than it should for routine banking services.

Venetoulis said the system by which earnings on the state's deposits are balanced off against charges for banking services has not taken rising interest rates into account, causing the overpayment.

Pat McGrath, press secretary for the Lee campaign, responded immediately that this "is clearly not the responsibilty of Gov. Lee. It is the responsibility of the state treasurer, an independent state officer who is elected by the General Assembly. This is not part of Lee's stewardship and is not an appropriate campaign issue."

Venetoulis, the Baltimore county executive, made the charge after culling through figures released in the annual state treasurer's report and comparing them to published state contracts with the three Maryland banks that have the state's accounts.

Two years ago, according to the treasurer's report, the state changed the way it paid banks for servicing the state accounts. The treasurer decided that all the banking services received by the state were worth $196,463 and calculated that this meant the banks could keep a cumulative $4.2 million balance. This amont, the treasurer calculated, would earn the $196.463 interest. However, Venetoulis said, the interest rate is higher today than in 1976 and the banks are actually earning $294,000 in interest on the state's $4.2 million balance.

Under his administration, Venetoulis said, Baltimore County's account was bid for openly and one bank agreed to provide the county with banking services without charge and without requiring the county to leave a balance in its account, as the state now does.

Under the new Baltimore County method, the county's bank account is cleared each night and the money is automatically invested for the county. it has meant nearly $1 million in interest earnings for Baltimore County. For the bank, it has meant free publicity and new customers among the county employes, Venetoulis said.

In contrast, he said, the state pays 7.5 cents for every payroll check it issues, some 70,000 checks every two weeks.

Venetoulis said he brought up the issue because he feels it exemplifies how state government should save money, reduce expenditures and ultimately reduce taxes. "Management of the state without politics, without doing old-fashioned banking that favors banks, is one of hardest aspects of running a government. . . The state's current banking system is not only wasteful, it is clearly indicative of the waste that premeates a government that clings to the status quo, a government that fails to question traditional practices," he said at a press conference.

"Lee should'nt hide behind the skirts of his treasurer. He is running on his record. A governor has a say in the entire administration. If lee wanted to, be could have called in the treasuere and asked what was the best way to manage the state's money and then done something about it," said Venetoulis.

Venetoulis also boasted that under his county administration the government does not pay for any payroll services, while the state pays 7.5 cents for every check it tissues, some 70,000 checks every two weeks.

Lee could not be reached for comment. His press secretary said the issue was inappropriate for the campaign and therefore he would not disrupt Lee's campaign schedule on the Eastern Shore.