Explosive used in failed SA ATM robbery

An explosive liquid has been used in an attempted ATM robbery outside the Adelaide Zoo, which is expected to be closed for much of the day.

Police say the front of an ATM near Adelaide's Zoo has been destroyed but no money was taken. (AAP)

An explosive liquid, never before used in Australia as a makeshift bomb, has destroyed part of an ATM in an attempted robbery outside the Adelaide Zoo.

The front of the machine was blown off in the parklands early on Friday morning but the rest of the ATM stayed intact and no money was stolen.

"We don't know the exact details of the device or what was in it or how it was constructed," Sergeant Phil Clague told reporters.

Sgt Clague said it was the first time the liquid, normally used by industry to harden plastic, had been fashioned into an explosive device.

He labelled the would-be thieves "reckless, dangerous and desperate".

Zoos South Australia said it was sad that people had targeted a conservation charity, with the incident closing the venue for much of the day.

"It is disappointing that this crime will limit people's access to the zoo," chief executive Elaine Bensted said in a statement.