Justice Minister Alan Shatter has claimed a recording of Gardaí making remarks of a sexually suggestive nature at a Corrib protest in Mayo were tampered with.
The recording was made following the arrest of two women at a protest against the controversial Corrib pipeline.
But the Shell to Sea protest group said it did not accept the recording had been interfered with.
Spokesperson Caoimhe Kerins said other files were removed from the disc before it was handed to the Garda Ombudsman, but the entire file for that day was made available.
And it was revealed earlier that Gardaí , who were disciplined and investigated following the recording, will not face criminal charges.
Mr Shatter made the revelation while answering questions from RTÉ on the investigation.
The Garda Ombudsman began a public interest inquiry three months ago following the Mayo 'rape tape' controversy.
Campaigners opposed to the Corrib gas project alleged that sexually suggestive and disturbing remarks were made by gardaí following the arrest of the two women.
A video recorder was confiscated and not switched off - and this recorded members of the gardaí speaking about rape.
All five gardai in the car when the comments were made were interviewed by Garda Ombudsman.
The interim report says investigators established within two days that three of them 'took no active part in the contentious part of the conversation, did not engage with the inappropriate comments or make any inappropriate comments themselves.'
The Ombudsman has now decided that while the other two - a Garda and a Sergeant - remain the subject of a disciplinary inquiry, none of the five will face criminal charges.
On Friday 8 April this year, the Garda Commissioner apologised for the comments.
Martin Callinan said he was sorry for the offence caused to the 'community we serve' and for the hurt and pain felt in particular by victims of sex crime.