One of Channel Nine's most senior reporters, Ben McCormack has been charged by NSW Police over sexually explicit conversations with another male about child pornography.

The A Current Affair reporter was arrested on Thursday morning at his Sydney home and taken to a nearby police station for questioning over child porn allegations after raids on the network's offices in Sydney.

Footage released by police shows McCormack being questioned by officers before he was charged.

McCormack, who was A Current Affair's hatchet man covering child sex monster Robert Hughes, is accused of being the type of individual he exposes for a living.

On Thursday he was charged with sending child pornography material after being arrested by detectives from the Sex Crimes Squad.

In Thursday night's episode of the show, presenter Leila McKinnon acknowledged the charges, saying McCormack had been suspended.

Ms McKinnon said that given the "serious nature of the allegations" Nine had decided to take a "strong position" against the 25-year veteran reporter.

She said the show had a long history of pursuing offenders in "these types" of matters and intended to cover the case of one of their "most senior reporters" without "fear or favour".

Ms McKinnon said that the footage of McCormack's arrest was blurred by NSW Police and not by Nine.

"These charges related to personal conduct," she said.

A NSW Police spokesperson said the Sex Crimes Squad’s Child Exploitation Internet Unit (CEIU) conducted ongoing investigations into the sexual abuse and exploitation of children online under Strike Force Trawler.

“Strike force detectives commenced an investigation after becoming aware of a matter via the Joint Anti Child Exploitation Team (JACET), a joint-agency approach to tackling crimes against children,” a police statement read.

“Police will allege in court the man was engaged in sexually explicit conversations about children with an adult male and discussed child pornography.”

McCormack's media peers swarmed Redfern Police Station on Thursday night.

It's understood fellow staff members at Nine had no idea McCormack was being interviewed by police, as officers raided the network's A Current Affair office in Willoughby, 7 News was told.

It's said other staff were "astonished" and "dumbfounded" to learn of the raid.

“About 7.30am today (Thursday 6 April 2017), the 42-year-old man was arrested by strike force detectives during a vehicle stop on Driver Avenue, Moore Park,” NSW police said on Thursday afternoon.

“Shortly after, detectives executed a search warrant at a home unit in Alexandria, and an office at Willoughby, where they seized computers, a mobile phone, and electronic storage devices.

“The man was taken to Redfern Police Station and charged with using a carriage service for child pornography material.”

A Nine Network spokesman said A Current Affair staff were helping police.

"The police are in the ACA offices doing an investigation and we are co-operating fully," he told AAP.

"The matter is a personal one and not related to a story or the program."

McCormack, who is also a surf lifesaver, described himself online as a pilot, humanist and twin.

McCormack has been granted strict conditional bail to appear at Downing Centre Local Court on Monday May 1.

Investigations are continuing.

If convicted, McCormack faces a 15 year jail term.