A man charged with brothel keeping as part of a police investigation into INLA activities also allegedly targeted five building sites in an extortion racket, the High Court was told.
It was claimed 60-year-old Brian Gillan visited contractors in the Crumlin and Glenavy areas of Co Antrim weekly seeking protection money.
One firm alone paid out £560 a week to ensure no property was damaged or stolen, according to the prosecution case.
Details emerged as Gillan, of Lurgan Road in Glenavy, was refused bail.
He was among two men and a woman arrested during raids in Belfast and Co Antrim last month targeting the republican grouping.
More than 200 PSNI officers took part in the operation, supported by the National Crime Agency and HM Revenue and Customs.
Gillan denies counts of keeping a brothel operating in Agincourt Avenue in Belfast, possessing criminal property and blackmail.
A Crown lawyer said he was detained in connection with suspected INLA membership and fundraising - but it was stressed that he has not been charged with any paramilitary offences.
Instead, the court was told police observations, photographs and witness statements links him to the alleged building site extortion from September 2017 until his arrest.
Prosecution counsel claimed evidence shows him attending businesses each Friday to make collections.
"Building sites and persons within them are blackmailed to pay money under the guise of protection money," she said.
"Failure to pay that money results in sites being damaged and property stolen from those sites."
Gillan, who is on disability benefits, had up to £1,000 in cash on him when he was detained.
He also allegedly acted as the "front man" for the Belfast brothel said to have been run by Florin Ghita, 32, and 22-year-old Christina-Teodora Musa - both Romanian nationals.
According to the prosecution he placed Romanian prostitutes in the property and collected £1,000 a month, from which he paid the rental lease.
During police interviews Gillan denied knowing anything about sex work going on at the address.
Defence counsel Jonathan Browne emphasised his client faces no allegations of terrorist offences.
He told the court the accused had worked in the building trade until his physical condition left him dependant on disability allowances.
Mr Browne also set out how Gillan had been in a relationship with Musa, holidaying with her in Romania and believing Ghita to be her cousin.
"He was ignorant of any other females being present at the (Agincourt Avenue) property," the barrister added.
Denying bail, however, Sir Anthony Hart cited the risk of re-offending.