Chia-Chia, a frisky, "fine healthy specimen of a male" giant panda, is being flown from London to Washington next month in an effort to kindle a romantic liaison with Ling-Ling, the National Zoo's stubbornly childless female giant panda.

Ling-Ling's new beau, whose name is pronounced Cha-Cha, will be relieving the allegedly inadequate Hsing-Hsing, whose six years of failure in impregnating his Chinese mate, or even showing much interest in a little hanky-panky among the bamboo shoots, have left zoo officials as frustrated as his would-be mate.

Described by London Zoo officials as a 240-pound, 8-year-old virgin, Chia-Chia is two years younger than Hsing-Hsing. Despite his rejection as a suitor, Hsing-Hsing will remain at the National Zoo in a room adjoining Ling-Ling and her new lover.

But Colin Rawlins, director of the London Zoo, cautioned against premature speculations that the mating will be successful.

"There is no certainty this [younger] chap will do his stuff any better," Rawlins said in an interview. "Washington believes our animal might do better" in springtime fling with his 11-year-old intended.

The spurned Hsing-Hsing apparently was "not good at doing what comes naturally," Rawlins said.

Local zoo officials said they still have not worked out details for accommodating Hsing-Hsing's rival, but one official said Chia-Chia probably will spend most of his time in a spare third room in the specially constructed panda suite.

When asked how the three pandas would get along, Theodore H. Reed, zoo director, said, "We'll have to wait until the orgy starts." Reed declined to discuss the transaction until the London Zoo makes an official announcement. News of the impending panda matchup was first disclosed in yesterday's Sunday Times in London.

For years, Hsing-Hsing has borne the brunt of responsibility for his and Ling-Ling's repeated inability to bear offspring. However, a National Zoo official said yesterday that it is not at all clear the problem has been entirely his.

Ling-Ling had an injured foot the first time Hsing-Hsing made a pass, the zoo official said, and rolled over because she could not support her mate. But now, even though her foot has long since healed, Ling-Ling continues to roll over whenever Hsing-Hsing makes one of his rare amorous advances.

On the other hand, "he's never caught on," the official added. Attempts to inseminate Ling-Ling artifically with Hsing-Hsing's sperm failed last year.

Although his virility has been certified in medical examinations, Ling-Ling's new suitor is as yet untested. His mate in London, Ching-Ching, underwent stomach surgery just before the couple was to have mated. Although she has since recovered, London officials fear she may not be strong enough to undergo the rigors of pregnancy.

As a result, Chia-Chia, who spent much of the last year alone in his cage while his mate was ill, was available for duty in the United States, Rawlins said. Chia-Chia will be flown here on March 5 and have some time to unwind from jet lag before the peak mating period in May. Rawlins said he expects Chia-Chia to be back in London by early June, "by which time anything that is going to happen should have happened."

Chia-Chia "hasn't had a chance yet" to test his mettle, Rawlins said. "You can't tell [if he will be able to succeed where Hsing-Hsing failed] until you try." And even if the new suitor fails, just the presence of another male might bring out the best in Hsing-Hsing. "The Chinese report that a bit of competition might help," he said.

Only 13 giant pandas are kept in zoos in the West, and so far the only cub born outside China was in the Mexico City Zoo last year. That cub was accidently suffocated when its mother sat on it a few days after its birth.

Rawlins estimated it would cost about $2,500 to send Chia-Chia and some attendants to this country. No overall budget has been worked out, he added, but total costs will be split by the two zoos.