Adelaide Zoo has thrown a birthday party for star attraction Fu Ni, but the panda’s keepers hope the gentle giant might soon be able to give them something in return.

Fu Ni, who turns nine on Sunday, arrived at the zoo in 2009, accompanying her slightly older male companion Wang Wang who turns 10 next week.

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But the pair have so far failed to breed, despite much hype every year either side of the 36-hour fertility window.

With the annual mating season approaching, panda keeper Monika Lapka said this year would be the best chance yet for the pair.

“Hopefully, she’ll repay us with a baby,” she said.

“Some time over the next month we will definitely be naturally breeding them and potentially artificially inseminating her.”

Ms Lapka said Wang Wang had so far failed to impress Fu Ni, but that might change now that he was reaching maturity.

“In the wild, the male needs to prove that he is dominant, so we’re really waiting on Wang Wang,” she said.

One of the cubs is examined by a veterinarian. Picture: Becky Malinsky

“Fu Ni is quite a strong personality; she’s quite a full-on personality and quite dominant herself, so it’s going to be quite a feat for him to become dominant.

“She will definitely play hard to get. We’ve seen that in the past.”

Fu Ni was treated to a giant birthday card and extra helpings of some of her favourite foods.

“She got panda cake, which is made mostly of mulched up bamboo with some sugar and some eggs and some flour and some minerals as well.”

Meanwhile, The Smithsonian National Zoo in Washington says its rare giant panda called Mei Xiang has given birth to twin cubs.

The first cub was born on Saturday at 5:35pm and the zoo said on Twitter that a second was born at 10:07pm.

The zoo has said both cubs appear healthy.

If the cubs survive, they would be the 17-year-old panda’s third and fourth surviving offspring.

Mei Xiang’s first cub, Tai Shan, was born in 2005 and returned to China in 2010.

Her second cub, Bao Bao, turns two-years-old on Sunday and still lives at the zoo.