His comments come as EU and British negotiators this week attempt to hammer out a draft transition deal amid continued stumbling blocks ahead of a crucial EU leaders’ summit next week.
Tensions are mounting after suggestions from London that people may have to pre-register on the island of Ireland before crossing the border after Brexit.
Speaking in Hong Kong as part of his St Patrick’s Day visit to China, Mr Coveney explained how the invisible border with the North had facilitated easy trade and movement of people.
“That has been a real stabiliser in terms of the peace process,” said Mr Coveney.
But this is about a lot more than trade, it is about the normalisation of life on the island of Ireland so there aren’t barriers to the movement of people and goods like there were in the past when there was a physical border infrastructure on the island. So we are very protective to make sure that doesn’t return.
Mr Coveney said he believed that the British government was committed to making sure there was no border infrastructure after Brexit.
EU and British teams are this week returning to phase one of the Brexit negotiations to iron out differences on the divorce bill, citizenship rights, and the contentious border question.
An EU summit in Brussels next week will consider these issues, a draft transition agreement, and matters around a future EU-UK trade pact.
There is still disagreement over the border, with London last week ruling out a suggestion the North could ultimately stay inside the EU customs union and therefore stop any new checkpoints.
While Brussels has agreed that the transition period for Brexit will end in December 2020, Mr Coveney suggested in an interview with Bloomberg that it may last longer.
If it needs to be extended, well then it can probably be extended for a short period after that if that’s what’s necessary, he said.
Meanwhile, there is growing opposition to a suggestion from a leaked British report that people crossing the border could be asked to pre-register.
Taoiseach Leo Varadkar immediately ruled out such a scenario. Any new checkpoints would become targets, he said.
“But if you do have physical infrastructure, if you do have cameras, and signs and border posts, those things will become targets,” he said.