Hedge fund manager David Einhorn took his “campaign” against Lehman Brothers to the airwaves yesterday, arguing that the Wall Street giant needs even more new capital.

Einhorn, whose Greenlight Capital is shorting Lehman stock, warned that “we are nowhere near the end” of Lehman’s writedowns and losses.

“Lehman is undercapitalized,” he said on Bloomberg Television. “They continued doubling down as the credit crisis evolved.”

“It’s essential, from a public interest, that these investment banks de-lever in a very material way,” Einhorn added. “That will require raising significant amounts of capital.”

Einhorn has berated Lehman of late, accusing the firm of hiding $6.5 billion in collateralized debt obligations and insisting that the bank remains in trouble. For its part, Lehman dismisses Einhorn’s comments as self-interested and baseless.

“Mr. Einhorn cherry-picks certain specific items from our 10-Q and takes them out of context and distorts them to relay a false impression of the firm’s financial condition, which suits him because of his short position in our stock,” Lehman said. “He also makes allegations that have no basis in fact with the same hope of achieving personal gain.”