Detectives from the Child Abuse and Sex Crime Squad's Child Exploitation Internet Unit began engaging online with a man from Sydney's southwest on Monday.

Police will allege in court the man believed he was speaking to a 14-year-old girl and engaged in conversations about sexually-explicit acts he wished to perform on the child and sent sexually-explicit material.

It will also be alleged the man was using his mobile phone to engage in conversations while at work.

Following extensive investigations, detectives arrested a 61-year-old man at Rosemeadow, just before 3pm on Tuesday.

Soon after, a search warrant was executed at a home at Woodbine, where detectives seized a laptop, a mobile phone and other electronic devices.

The man was charged with use carriage service to groom a child under 16 years for sex, two counts of using a carriage service to send indecent material, using a carriage service to solicit child abuse material, using a carriage service to transmit, publish or promote child abuse and producing child abuse material.

He was refused bail and will appear in Campbelltown Local Court on Wednesday.

Australian Associated Press