Virginia Gov. Charles S. Robb, attempting to strengthen a minority business program that critics have long derided as toothless, has directed state agencies to establish voluntary goals for contracts with minority-controlled enterprises.

State officials said today that, although the goals have yet to be established, the performance of the agencies in meeting them will be closely monitored by a new interagency council to be headed by Secretary of Commerce and Resources Betty J. Diener. This brought instant criticism from a key Republican legislator who suggested the program could meet resistance from the General Assembly.

"I don't think the state should be in the coercion or arm-twisting business," said state Del. Vincent F. Callahan of Fairfax, the House minority leader. "If we're talking about taxpayers money, it ought to go to the lowest bidder.

"The state ought to be promoting all business in Virginia and not favoring one group over another," he said.

Carolyn Jefferson-Moss, Robb's director of the Office of Minority Business Enterprise, said that the new initiative does not constitute "set asides" or "quotas," which have been repeatedly rejected by the legislature.

"It's a completely voluntary program," Moss said. "We're not going to force anybody to do anything."

Although Virginia has had a minority business office since 1975, it has long been criticized by black businessmen as an anemic agency that has had little success in directing state contracts towards the approximately 1,000 minority owned vendors in the state. With a staff of 11 and a budget of $327,000, critics say the office had little clout during the administration of Republican Gov. John N. Dalton and rarely informed minority businesses of impending contracts.

"It was dormant," said state Sen. L. Douglas Wilder, (D-Richmond), of the minority business program. "There was little effort to reach out to minority businesses. It didn't have any teeth."

About one-half of 1 percent of all state business is currently handled by minority businesses, according to state figures.

Robb's new initiative, outlined in a memo sent to all state agency directors last week, is designed to beef up the program through a variety of methods. Among them:

* A proposal to establish a state chartered "Certified Development Corporation," patterned after a program operated by the Small Business Administration, to provide loans to minority and small businesses.

* A set of guidelines to direct the flow of state funds into the state's nine minority-owned financial institutions. Currently, the minority banks and savings and loans handled about $900,000 in state deposits out of a total of about $50 million.

* The creation of an Interdepartmental Council on Small and Minority Business Enterprise, headed by Diener, to devise agency goals for increasing minority procurement and monitor them. Diener said today that she could not estimate what the goals will be. "But when you're at one half of 1 percent, anything you do is up," she said.

* State participation in the Virginia Minority Supplier Development Council, a federally funded body that seeks to persuade private corporations to increase their purchases from minority businesses. Council director Willie C. Achebe said today that the organization has so far been unable to persuade many of the state's largest companies, such as the A.H. Robins Co. and Ethyl Corp. in Richmond, Allied Corp. in Hopewell, and the Mobil Oil Corp. in Fairfax, to participate in the program or join the council.

"Usually, they say, 'Now is not a good time to try us. Why don't you try again next year?'" said Achebe. "After a couple of times of trying, you get the feeling they're not interested."