An Australian zoo has been evacuated after an orangutan escaped after using a branch to scale an electric fence around her enclosure, zoo officials have said.

An Australian zoo was evacuated Sunday when an orangutan escaped after using a branch to scale an electric fence around her enclosure, zoo officials said.

Adelaide Zoo said patrons were evacuated as a precaution when 27-year-old Karta, described as "extremely intelligent", breached the electric fence on Sunday morning.

Zoo curator Peter Whitehead said Karta got as far as a boundary fence but was still some distance from the public before seeming to realise she was in the wrong place and returning to her enclosure.

Whitehead said although the primate showed no during her 30 minute escapade, she was secured inside her night den before the public were readmitted.

"She was probably secured by the time we got most of the people out of the ," he told Sky News.

(c) 2009 AFP