One family ended up much closer to the animals than expected, after coming across one chimp freely roaming the grounds.
The highly intelligent primates had used their wits and a tree branch brought down by Storm Erik to scale a wall.
While order was later restored, questions are being asked about safety.
East Belfast UUP councillor Chris McGimpsey has long been a critic of Belfast Zoo and is calling for at least a temporary closure to review the situation.
“The escape of five chimpanzees was a potentially dangerous situation which could have ended with very serious consequences for the general public,” he said.
“For some time now, I have voiced my concerns at how Belfast Zoo is operated and I have called for its permanent closure.
“At the very least, the zoo should now close for two weeks to enable a thorough appraisal to be undertaken so that the safety of animals and visitors can be ensured in the future.”
In a statement, Belfast City Council said what happened at the facility on Saturday was “a highly unusual event”.
They’re intelligent primates and know they’re not supposed to be out of their enclosure, so got back in themselves.
Efforts are being made to establish if the branch which enabled the escape fell after morning checks were carried out.
Belfast Zoo added: “Additional security checks are also being carried out at other enclosures following this incident, to ensure the health and safety of both animals and visitors, which remains a key priority for our dedicated team.”
The incident comes after a red panda escaped from the grounds just two weeks earlier.
Last summer, a spider monkey died after escaping from the zoo and being hit by a car on the M2 motorway in north Belfast.