The Virginia Senate approved two sweeping measures today that would abolish interest rate ceilings on bank and retail store charge accounts by allowing interest rates to rise to their free-market level.

The bills, which already have cleared the House of Delegates and have been endorsed by Gov. Charles S. Robb, are likely to mean higher finance charges on 1.5 million MasterCard and Visa credit card accounts issued by Virginia banks.

Also affected would be charge accounts offered by thousands of retail stores, ranging from large department stores such as Sears Roebuck and Co. and Montgomery Ward & Co. to small groceries and drug stores.

Passage of the credit card bill -- the top priority of the state's powerful banking lobby -- was marked by a fierce debate over conflicts of interest that saw nine senators with private banking interests, or nearly one fourth of the 40-member body, abstain from voting.

Many other senators who have financial interests in banks, including at least one bank president, voted for the bills.

Today's actions, which would take effect April 1, 1983, would wipe out a longstanding 18 percent lid on the interest rate that banks and retail stores can charge their credit customers on unpaid balances. Bank spokesmen have predicted that because of competition among banks, interest rates will rise under the measures to no more than 19 or 20 percent.

Opponents today charged the measures would "throw consumers to the wolves." They also ridiculed bankers' claims their credit card operations are so unprofitable that, without passage of the bill, they would be forced to move them to nearby states, such as Delaware, where credit ceilings have been erased.

"The only reason they issue credit cards is to make money," shouted Sen. L. Douglas Wilder (D-Richmond). "They're not issuing credit cards to help people . . . When we hear them saying they're going to move to Delaware, I say, 'Go to Delaware.' "

The Senate did approve, by a 16-to-15 vote, an amendment intended to help consumers by prohibiting the $15 membership fees Virginia banks began imposing on their charge card customers last year. The bankers, caught off guard, vowed to knock the provision out when the bill goes to a House-Senate conference committee.

The credit card deregulation measures have been the major goal of the state's bankers and the Virginia Retail Merchants Association since last year when similar legislation was killed in a House committee.

The Virginia Bankers Association waged a lobbying campaign that included at least $42,000 in undisclosed campaign contributions to state legislators during last fall's election. The intensity of the effort, in contrast to the virtual absence of any full-scale spokemen for consumer interests, was underscored during today's floor debate.

"Rarely do you see anyone down here except the lobbyists," complained Sen. Dudley (Buzz) Emick (D-Botetourt), who opposed the measure. "There are a lot of citizens that count on us to represent their interests, but it's easy to lose sight of that when you have the lobbyist from the bankers -- who's a friend of mine -- grabbing my arm outside of committee and saying, 'Buzz, we need you.' "

The debate over the bill, however, was almost a sideshow to the more heated arguments over conflicts of interest.

As the first roll was called and the nine abstaining senators rose one by one to invoke Rule 36, the Senate's conflict-of-interest provision, supporters of the credit card bills grew alarmed and implored their colleagues to reconsider.

"I would ask the senators, does the fact that they sit on a bank board or have a position with a bank mean that they think they control the price of money?" said Sen. Peter Babalas (D-Norfolk).

"If everyone is going to run for cover," added Sen. William Fears (D-Accomack), "we're not going to have enough votes to pass this bill."

Fears earlier obtained a special subcommittee ruling that it was not a conflict of interest for senators with bank stock holdings to vote on the credit card bill unless the measure affected their banks specifically.

But the virtually unprecedented round of abstentions reflected concerns that have troubled many senators following conflict-of-interest charges against Sen. Nathan Miller (R-Rockingham), last year's Republican candidate for lieutenant governor.

Sen. Willard Moody, who two years ago was hit by conflict charges after he moved to kill a bill opposed by a railroad union that had paid him hundreds of thousands of dollars in legal fees, opted to abstain on the credit card bill even though, as Rules Committee chairman, he appointed the subcommittee that issued the conflict ruling.

The Portsmouth Democrat said he did not think it would have been improper for him to vote on the bill even though he sits on a bank board, owns bank stock and represents the Bank of Virginia in his private legal practice. "But I could see where it would be questionable," Moody said later. "I could see where my constituents could say, I represent a bank and here I am voting to give them unlimited charges on credit cards."

The bank card bill passed 21-to-7 and the retail store measure by 30-to-5. Many senators said later the amendment dropping membership fees would have failed had it not been for the unusually high number of abstentions, which cost the votes of probanking senators.