Child abuse material seized in recent raids across Victoria included images of babies being subjected to violence and torture, police say.

Twenty men were arrested in the raids targeting online child abuse material, and 13 were charged with offences including possessing child exploitation material, transmitting child exploitation material and drug offences.

Victoria Police Deputy Commissioner Shane Patton described the seized material as "horrendous" and said police believed the children in the material were located overseas, and some had already been rescued as a result of previous operations.

"It involves them in poses that are sexually provocative, it involves them being subjected to violence, it involves them being in degraded acts, and it also involves torture in some occasions," he said.

"To view this material, to make this material, to share this material, it's abhorrent, it's offensive and it's disgusting."

In addition to the 13 men charged, three others are expected to be charged on summons, and four were released pending further inquiries.

Deputy Commissioner Patton said one of those charged was a school teacher.

The principal of St John's Regional College in Dandenong, Tim Hogan, said a staff member had been immediately suspended from work after police informed him of the allegations last week.

"The staff member has had no contact with students since the school was made aware of the allegations," he said.

Police arrested 20 men aged between 19 and 62 years. ( Supplied: Victoria Police )

'Hundreds of Victorians' sharing abuse material

The Deputy Commissioner said police hoped the raids would send a strong message to offenders that they would be caught.

"You would be amazed to know that every month, hundreds of Victorians are sharing millions of images of child abuse material, both movies and images," he said.

"There will be people sitting at home in suburbs in Melbourne at the moment viewing child abuse material, thinking that they're safe and they're immune and they're not going to be targeted by the police.

"We will target them. These are people who wouldn't consider going down the street and breaking into a store or anything, but what they're doing is watching some of the most vile, degrading offending that's known to this planet."

Police remove evidence from a house following one of the raids. ( Supplied: Victoria Police )

Dolls, drugs and samurai sword seized

Victoria Police and Australian Federal Police officers executed 20 warrants in March at properties across Melbourne, in Geelong, at Capel Sound on the Mornington Peninsula and Heathcote in central Victoria.

They seized computers, tablets, mobile phones, child sex dolls, illegal fireworks, a samurai sword and illicit drugs during the raids.

The men arrested were between 19 and 62 years old.

Deputy Commissioner Patton said online child exploitation was one of the fastest growing crimes in the world, fuelled by social media platforms and advancing technology.

"There is clear evidence that child exploitation material is sometimes used for grooming and seducing victims," he said in a statement.

"Part of this operation was focused on establishing whether any of those arrested had moved from online offences to contact offending, and if there were any children currently at risk or who could be identified as victims of a sexual assault.

"These are not simply online choices made for sexual gratification — they are abhorrent crimes against children, the most vulnerable people in our community."