A 1982 security report on policing described An Garda Siochana as a "technically unsophisticated" force which was under-resourced and intensely sensitive to any perceived criticism from outside.
Brooks Richards, the then security co-ordinator to the secretary of state for Northern Ireland, said it would take the gardai several years to reach the level of skill of their equivalents in the North.
He said there had been a significant increase in co-ordination between the British and Irish since the mid-1970s but added that the gardai "have a long way still to go".
The report continued: "They have made some useful finds of arms and explosives, but there have been very few convictions in the Republic of terrorists from border areas."
However, while there was a perception that gardai were unwilling to act against the IRA or had a lack of professional capability, there was little evidence to justify this.
"The most significant deficiencies in this technically unsophisticated and basically unarmed force include a lack of resources to acquire and process intelligence, an inadequate surveillance capability and general shortages of manpower and material," wrote Mr Richards.
The best way forward for co-operation between the two sides was to have minimal political intrusion and publicity.
"They are extremely sensitive to any comment which could be interpreted as external criticism," he advised.
Meanwhile, it has emerged that the shadow Northern Ireland secretary, Airey Neave, may have been assassinated as a result of leaks about the Conservative Party's policy, which were fed to terrorists.
"Enoch believes that Airey's determination to pursue a unionist policy in regard to Northern Ireland was then communicated to the INLA, which then decided to eliminate the man whom it perceived to be the threat to the prospective unity of the island of Ireland," the memo states.