CBS Inc. lawyers and lobbyists mounted an aggressive defense against broadcaster Ted Turner's hostile takeover bid on two fronts yesterday, in Washington and in Albany, N.Y.

In Washington, CBS urged the Federal Communications Commission to hold lengthy hearings to determine if Turner should be allowed to proceed with his bid to acquire the company. Turner has said he will not purchase any CBS stock until after he receives FCC approval. If the FCC decides to hold lengthy "evidentiary" hearings, which is not considered likely, Turner's takeover bid could be delayed for many months.

Meanwhile in Albany, CBS gained an advantage over Turner when the New York legislature overwhelmingly approved a bill that could prevent Turner, or any other bidder making a noncash offer for a New York corporation, from acquiring more than 20 percent of a company's stock without the approval of the company's directors and two-thirds of its stockholders. Gov. Mario Cuomo said he will study the bill before deciding whether to sign it.

Lawyers for Turner were trying to convince the legislature late yesterday to pass an amendment that would exempt the CBS takeover bid, since the offer is in progress. A Turner spokesman said the Atlanta broadcaster intends to challenge the constitutionality of the bill if it is signed by the governor.

"The Turner Broadcasting System is asking New York state legislators to adopt an amendment to the just-passed bill which makes unsolicited, noncash takeovers of New York corporations virtually impossible," the company said in a statement. "TBS is seeking an adoption of a 'fairness' amendment which would exempt ongoing transactions.

" . . . Provisions of the bill are designed to entrench management and are, we believe, unconstitutional and violate basic shareholder rights. If this legislation is signed into law as presently written, we will mount a swift constitutional challenge on its face and as it applies to [our] offer."

Turner's offer could be thwarted by the bill because it includes no cash. Instead, Turner offers CBS stockholders a complex package of securities, including risky, high-yielding junk bonds, in exchange for their stock. He plans to finance the proposed takeover by selling many of CBS' non-broadcasting businesses.

Several knowledgeable investment bankers have said that they believe CBS will be forced to take major steps, such as repurchasing some of its own shares to increase its stock price, in order to defeat Turner's bid. If CBS increased its stock price by repurchasing shares at a substantial premium above the market price, Turner's bid, worth about $150 a share according to Wall Street analysts, would no longer be as attractive to stockholders because there would be little difference between the value of his offer and the price of CBS stock.

In urging the FCC to hold extensive hearings that could delay Turner indefinitely, CBS said Turner is not financially qualified to acquire the company. CBS said that Turner's noncash offer is very risky. If Turner is allowed to proceed, "the only remaining question is . . . not will CBS go bankrupt, but when will it go bankrupt?"

CBS attacked several financial assumptions Turner made in his FCC filings. The FCC technically only needs to certify that Turner would have sufficient financial resources to operate the CBS television stations for 90 days, but CBS wants the commission to apply a higher standard since the transfer of major television network is involved.

CBS also told the FCC yesterday that if Turner acquired the network, it would reduce broadcasting diversity, since the Atlanta broadcaster owns a competitor, Cable News Network.

The FCC is not expected to make a final decision until sometime this fall on whether to let Turner proceed.