Around 900 Garda officers have been tasked to a massive security operation on the southern side of the Irish border ahead of the G8 summit.
Plans have also been drawn up for special courts and extra detention cells at locations in the Irish Republic, from Donegal to Monaghan.
Garda Assistant Commissioner Kieran Kenny, who is in charge of border counties, said the force was in contact with security services within a number of different countries, as well as international agencies Interpol and Europol.
"For an event of this magnitude, the what-ifs list is endless," he said.
"So in so far as we can point plans will take account of worst case and best case scenarios."
A number of delegations attending the summit are staying in the Irish Republic.
Mr Kenny said there were plans for a "mix" of threats, including the risk of local dissident republicans using the occasion for global publicity.
But the Garda chief said they had no estimate at this stage - just weeks ahead of the talks - of the numbers of protesters expected.
Although a large protest is expected in Dublin, surveillance of ports and airports and the movement of people throughout the island will form a major part of the security operation.
Authorities have refused to give any details about the expected cost of the security operation to Irish taxpayers ahead of the talks at the Lough Erne Resort in Co Fermanagh, Northern Ireland. Eight temporary border checkpoints are to be manned by Garda units backed up by the Irish Army, alongside rolling checkpoints by mobile patrols.