Police have raided the offices of
and arrested star reporter Ben McCormack over alleged child pornography offences.
Shocked staff members looked on as at least seven NSW Police officers entered the Nine Network's Sydney headquarters armed with evidence bags on Thursday morning.
Police searched the entire ACA office at Willoughby and seized a computer on site.
ACA journalist McCormack was arrested this morning at his inner-city home and taken to a nearby police station for questioning over alleged child pornography offences, the Daily Telegraph reported.
McCormack's lawyer Sam Macedone told news.com.au he hasn't had a chance to talk to his client "about what's been alleged".
"In respect to certain investigations that are being carried out by NSW Police, he's been arrested, and I expect he's going to be charged," Macedone said.
"I expect I will know what the allegation is soon.
"Police are not in a position to give that information to me."
News.com.au understands members of the network's legal team were in the ACA office at Willoughby as the police raid unfolded.
Staff members were asked to leave the office as a search warrant was carried out.
Channel 9 has confirmed a police operation was taking place at the station and said Nine was co-operating with police.
"There are police there (at ACA offices) and they are investigating," Nine's head of publicity Victoria Buchan told news.com.au. "We are co-operating."
Buchan said the investigation was not surrounding the program or a story, and was in relation to a personal matter.
A spokesman for NSW Police confirmed they had conducted the operation.
"The investigation related to a personal matter of an employee," the spokesman said.
Police inquiries are continuing.