"The biggest income stream will almost certainly be publishing which, even if radio play has stopped, will still be pretty big," he told Wales.
"This is because PRS and their equivalents in different countries allocate money on a spot-check basis.
"So you're going to get money for plays in gyms and hairdressers and on juke boxes and all that stuff.
"They will say, "This is how much music is in the market place so it is likely you are due this amount.
"He will also get a publishing cut for any play Lostprophets have anywhere."
The 36-year-old, from Pontypridd, admitted two counts of attempted rape on the baby of one female fan on the eve of a trial in Cardiff last month.
Watkins also admitted conspiracy to rape the baby of another female fan, sexually touching a one-year-old and possessing and making child porn.
He also plotted sex abuse with the mothers of the babies in a series of text and internet messages. Both women, who cannot be named, will be sentenced with him.
But fans around the world continue to play Lostprophets music and video footage of the band remains popular on internet sites such as YouTube.
Sadly, the case and Watkins's notoriety could also be generating a substantial pick up in album sales for the band he fronted.
"The records could be earning a substantial amount. It could easily have translated to 100,000 or 200,000 extra sales," Mr Brookes said.
"It could be over £100,000 easily. It could be less, but there will be another spike when he gets sentenced, in terms of money generated - because of clips when the story breaks, then there will be a spike in online activity.
"And there are going to be PRS payments because the music is out there."
Revelations surrounding Watkins' secret life of planned child abuse and debauchery have continued to emerge since his admission in court.
A former girlfriend has spoken publicly about the number of times she reported Watkins to the police after being horrified by his vile suggestions.
Another woman has spoken out claiming Watkins wanted to have a baby with her that he planned to sexually abuse.
Disgust at the depths of his depravity has seen him transformed from celebrated rock star to being universally reviled.
As his artistic activities continue to be broadcast around the world, however, royalty payments collected by the Performing Rights Society (PRS) and others will keep flowing in.
- Daily Mail
