Gigi the giraffe dies two weeks after being moved to Sydney Zoo

A giraffe has died at the new Sydney Zoo just weeks after moving there from Australia Zoo.

Three-year-old Gigi only recently arrived in western Sydney after being transferred from Queensland's Sunshine Coast.

But on Saturday night, the eve of World Giraffe Day, Gigi died.

Sydney Zoo said her death was sudden and unexpected.

"It is with a heavy heart that we say a very sad goodbye to Gigi," Sydney Zoo said in a statement.

"As we mourn this tragic loss, she will be remembered for her friendly and cheeky nature."

A post-mortem is being carried out by an expert team from the University of Sydney. The results are expected to be released in a few weeks.

Gigi was moved to western Sydney as part of a nationwide breeding program.

The zoo said she was fit, healthy and had settled in well.

But some experts are concerned.

Veterinary surgeon Dr Robert Zammit suggested moving from a hot to a cold climate could have placed stress on the animal.

A new companion will be sought for Sydney Zoo's remaining giraffe, Eyelean.