Farmyard security measures on the Troubles-era hard Irish border prompted disputed allegations of discrimination against Catholics, the files reveal.
Roads in Co Fermanagh leading into Co Monaghan in the Republic were closed because of the IRA threat.
They were effectively being opened to limited vehicle access by allowing landowners to make detours through lockable gates on their farmland, a decades-old British Government archive note said.
Northern Ireland Office official Peter Smyth explained: "The privilege of being allowed to install such gates is apparently not extended to the Roman Catholic community and has caused considerable resentment in the area.
"Old allegations of Royal Ulster Constabulary collusion with the unionist community are reviving."
Roslea is a village close to the border, around 25 miles to the south-east of Enniskillen.
In 1994 some nationalists living there felt Protestants were receiving favourable treatment when it came to accessing cross-border land, an archived British Government note released by the Public Record Office of Northern Ireland in Belfast said.
The dispute highlighted the localised impact of an Irish border, which had been closed for years because of the danger of republican attacks.
The official record from 1994 surrounded a meeting with an influential member of the community in Fermanagh, Gerry Lynch, and highlighted some of the social sensitivities around the 310-mile frontier.
Mr Lynch claimed Catholic farmers had approached the RUC to secure access through lockable gates, but been refused.
Mr Lynch maintained: "Any attempts by Catholic farmers to create temporary bypasses for purposes of bringing in crops quickly attracted the wrath of the police."
The NIO official added: "All the bypasses he knew of had been granted to Protestant farmers and the perception was growing that, once again, the local Catholics were being treated as second-class citizens."
Mr Smyth said the RUC considered applications for gates on a case-by-case basis.
He added: "I have no doubt I was given a fairly subjective account of the situation but there was no mistaking Mr Lynch's sense of injustice.
"Relations between the nationalist community and the security forces are always delicate around Roslea and Mr Lynch has worked harder than most to keep things on an even keel.
"He feels that he has gone out on a limb for the past two or three years and is genuinely disillusioned by the apparent failure of the local RUC to make some gesture of reciprocity."
The records also discussed security concerns about a future IRA attack on a police station in Co Tyrone using an improvised border crossing created by a farmer to straddle a stream on his land.
A four-wheel drive vehicle had been employed in previous attacks and the RUC wanted to excavate the stream to make it impassable to traffic.
The farmer suggested an alternative involving blocking access to the field, but was unable to ask local contractors to do the work for security reasons.