A Sydney man has been charged with child grooming after allegedly having several "explicit" online conversations with people he believed were 12 and 13-year-old girls, police say.
But the "girls" were actually undercover detectives from the NSW Police sex crimes squad.
A State Crime Command spokeswoman said police from the Child Exploitation Internet Unit were doing similar operations all the time.
"Police are constantly doing the operations online," she said.
"You never know who you might be talking to."
The detectives were given information from police in Western Australia and Queensland about similar alleged offences by the 48-year-old man, and assumed the identity of the girls online, police said.
"It will be alleged that some of the conversations were explicit," a police statement said.
The man was arrested at a business in the city yesterday afternoon and computer equipment was seized from his Hornsby Heights home.
He was charged with three counts of using a carriage service to groom a person under 16 years of age and two counts of using a carriage service to transmit indecent material to a person under 16 years of age.
He was given conditional bail and will appear at Downing Centre Local Court on May 31.
Police also issued advice for parents about safe internet use for children including talking to them about the potential dangers of chatting online and keeping the computer in an open family room.
Children were urged not to send pictures of themselves to people they don't know or put a detailed profile anywhere online.