Police nab alleged online sex predator

A man has been caught allegedly trying to ensnare a young girl for sex in an online chatroom after police posed as her mother.

The 47-year-old Riverstone man was netted by detectives who assumed the identity of a mother with a 12-year-old daughter and chatted to him on an adult social networking site.

He made sexually explicit comments about the hypothetical girl to her "mother" and tried to arrange to meet them at a Parramatta hotel for sex, police allege.

He was arrested in the early hours of Wednesday morning.

When police then searched his home, they seized computers and electronic devices, as well as four registered firearms.

He's been charged with using a carriage service for child pornography and incitement to commit aggravated sexual assault on a victim under 16.

He was granted strict conditional bail to appear at Parramatta Local Court on May 28.