Former Channel Nine reporter Ben McCormack sought treatment for his sexual attraction to children years before his arrest, a Sydney court has heard.

McCormack faced a sentencing hearing on two charges of using a carriage service to transmit, publish or promote child pornography.

The 43-year-old former A Current Affair reporter pleaded guilty to both offences in September.

He exchanged dozens of explicit messages with another man over Skype over a period of almost two years.

No pictures or videos were exchanged in the messages.

It emerged on Friday that McCormack first started receiving professional help for his paedophilic tendencies in 2008.

The treatment has been ongoing since then.

Judge Paul Conlon said the fact he was seeking assistance for something he knew was wrong was a significant factor to be considered in sentencing.

"I've never seen that before," he said.

Prosecutors asking for custodial sentence

Judge Conlon said the case was in a different category to virtually any other he had dealt with.

Referring to the first count, he asked the prosecutor rhetorically: "If this had been a conversation between two adult males, not over the phone, it could not have constituted this offence?"

The prosecutor agreed and accepted that the offending was at the low end of seriousness.

However, prosecutors are still asking the judge to consider a custodial sentence, pointing to the regular nature of the conversations and the fact they continued for so long.

McCormack's lawyers argued the messages were fantasy talk and were never acted on in any other way.

He will be sentenced on December 6.