Mr McBrearty Jnr said: “We need a mechanism in this country to expose the full extent of corruption.”
The network has grown to around 50 members since a meeting held in the McBreartys’ nightclub in Raphoe following the publication of the Morris Tribunal’s damming second report in July.
Mr McBrearty said he had been inundated with queries and complaints from people regarding not just the gardaí but many other State agencies and professions.
“If we have an independent mechanism in Ireland, then people will get justice,” he said.
Mr McBrearty said he had only been able to pursue his case because his family had been able to afford the legal expertise which he said was needed to get justice.
“We would like to see it (the anti-corruption network) grow, raise money and possibly take cases for people who don’t have money,” he said.
The network is due to hold a public meeting in the Mansion House in Dublin at 1pm on Saturday and is calling on people to bring detailed statements of their complaints.
Larry Wheelock, whose brother Terence died after being found unconscious in Garda custody, will speak at the meeting.
“There’s an awful lot of cover-up going on and the family want to know what happened,” he said.
Terence Wheelock, from Summerhill in Dublin, was arrested in June, along with three other men, in connection with the robbery of a disabled driver’s car.
He was put in a cell in Store Street Garda station and was found unconscious several hours later. According to gardaí, there was a cord around his neck which had been fixed to a fitting on the wall.
He never regained consciousness and died in hospital in September.
But Larry Wheelock said the family believed he had no connection with the robbery and that he did not take his own life.
“My brother was not suicidal in any way. I was with him that day, he was in great form 10 minutes before he got arrested. He had no history of depression.”
He said the family wanted an independent inquiry to investigate what he claimed were suspicious circumstances surrounding the death, including marks on Terence’s body, the renovation of the cell after the death and the failure to return his clothes to the family.
Detective Superintendent Oliver Hanley from Dun Laoghaire Garda Station is carrying out an internal inquiry into the death.
Osgur Breatnach, who was one of four men wrongly imprisoned for the 1976 Sallins Mail train robbery after confessing to gardaí under duress, said he would be speaking at the meeting because none of the lessons of the past had been learnt.
“Over the past 30 years, all the allegations that we made in relation to our case have been repeated time and time again,” he said.
His conviction was quashed in 1980.