Two of the three devices exploded, while the third was recovered intact.

Earlier on Sunday, police said they were on the lookout for a group of young people dressed as Santa in relation to the incident.

One device detonated and set fire to a rubbish bin near the Bendigo Library in Hargreaves Street on Sunday morning.

The other exploded device was found at the intersection of Myrtle and King streets.

The third device, described by police as a modified pipe bomb, was found intact in a container in Chancery Lane.

Police prevented it from exploding by using robots to safely deactivate it.

Arson and Explosive Squad detectives charged a 24-year-old Maiden Gully man with eight offences, including reckless conduct endangering life, manufacture of an explosive substance, criminal damage and causing an explosion likely to endanger life.

The man, has been bailed to appear at Bendigo Magistrates' Court on December 23.

Sergeant Steve Rainy said police were confident the explosions were "moronic" pranks and not acts of terrorism.

"This is just stupidity at its best, particularly in the current climate with events around the country," he said.

"It's nothing short of moronic to come out the weekend before Christmas with any type of explosive device and think detonating that is fun.

"It could have had catastrophic effects for someone over the Christmas period."

Sergeant Rainy said police would examine CCTV footage to assist their investigations.

It was lucky no one was hurt by the devices.

If someone had been standing next to the rubbish bin when it exploded they could have suffered significant injuries, he said, and there was "no knowing" how much damage the pipe bomb might have caused.

He said the bomb disposal unit worked on the second device at 6am, using robots to empty the device of powder, which is being tested.

The devices, discovered between 3am and 4am on Sunday, were home-made.

"These are fairly simple devices - someone has certainly made them at home," he said.

Parts of the CBD were cordoned off on Sunday while detectives from the arson and explosive squad investigated.