Five lions managed a short escape from their enclosure at Sydney's Taronga Zoo early on Wednesday, prompting the zoo to sound a "code one" alert and rush guests of its "Roar and Snore" overnight stay programme to safety.
The alert was issued after video footage showed four cubs and one adult lion outside their enclosure at 6.30am (1930 GMT) although they were still in an area separated from the rest of the zoo by a six foot fence.
Zoo keepers tranquilised and returned one cub while the remaining four made their way back of their own accord.
The zoo said its emergency response was enacted less than 10 minutes after the lions escaped the main exhibit area. The lions were confirmed to be back in their enclosure by 9am, local media reported.
There were no injuries to people or animals and the zoo opened as normal.
"The zoo has very strict safety protocols in place for such an incident and immediate action was taken," Taronga Zoo executive director Simon Duffy told a news conference.
The police were called to the zoo and staff hurried to lead guests of the "Roar and Snore" programme away from danger.
"They came running into the tent area saying, ‘this is a Code One, get out of your tent and run, come now and leave your belongings',” Magnus Perri, one of the guests, told local media as his family left the zoo.
Taronga Zoo, the city's largest, is home to seven lions, including five cubs and two adults, according to its website.
The zoo does not yet know how the animals escaped and has launched a formal review.