Ireland will try to ensure checks in a no-deal Brexit will be done away from the border, Tánaiste Simon Coveney has said.
He added Ireland would have to work to protect its place within the EU single market.
Doing this without the backstop will lead to "unpalatable decisions", the Irish deputy prime minister said.
Mr Coveney was speaking at an event in Dublin geared at preparing businesses for a no-deal Brexit.
"These are difficult choices," Mr Coveney said.
"We do recognise the reality that Ireland will have a responsibility to protect its own place in the EU single market and that will involve some checks.
"But I can assure you that we will try to do that in a way that limits the risk, and we will try and do it, obviously, away from the border."
Ireland's latest contingency plan, published in July, said no deal would mean cross-border trade could not be as frictionless as it is now.
But it does not elaborate on where and how such checks would take place.
The Revenue Commissioners, Ireland's tax authority, has suggested that while all customs declarations could be filed electronically, up to 8% of consignments would still need to be physically checked for customs purposes.
It says it is exploring ways of doing this at traders' premises or at designated warehouses.
The Irish government has said it is giving its no-deal Brexit contingency plans "top priority".
The cabinet met on Tuesday night to discuss the latest developments in Westminster, and said it noted that a no-deal Brexit is "increasingly likely".
The legal default position is that the UK is due to leave the EU on 31 October, unless an extension is granted.
The Irish government said it has issued an additional "call to action" to ensure that businesses are ready for the new regulatory requirements in the event of a no-deal Brexit.
Mr Coveney said the Irish government would not allow the country to be "dragged out of the EU single market by default as a result of Brexit".
"If we're not careful, we won't take the necessary action to protect the integrity of the single market, and therefore, our goods will be checked on the way into France, Germany or Belgium," he said.
"That would be hugely damaging to our business model and we cannot, and will not, allow that to happen.
"That is why we will face difficult choices in the context of how we introduce a checking system, somewhere, away from the border, for obvious reasons, that can protect the integrity of the single market and reassure other EU countries that share the single market with us that we don't have an open back door into the single market through Northern Ireland, if it's unguarded."