Dublin refuses to be 'backdoor' to EU market

"The response from Ireland's border customs team was one of real skepticism," Coveney said of the UK's proposals published two weeks ago, adding that Ireland is also keen on preserving an invisible border.

"We cannot be part of essentially creating some kind of a backdoor into the single market that is not properly regulated," he told reporters.

"There is more that could be done to add credibility to the solution before we move to transitional issues," he said of the UK's plans.

Britain wants to keep free trade between Ireland and Northern Ireland, but its proposed methods have been met with doubts both in Dublin and in Brussels.

"The EU task force is not convinced the UK's approach is going to solve the issues," the minister added.

The UK plans not to have any physical infrastructure at the border and wants technical solutions as a substitute, and see British authorities taking the responsibility of monitoring the border - even collecting EU duties.

Ireland is also interested in maintaining the status quo on the free movement of people, goods and services, but wants to avoid creating a possible hole in the single market's borders.

The minister recalled that 90 percent of Ireland's production is exported, and most of it goes into the EU market.

The European Commission is expected to come out with its own proposals on the issue of Northern Ireland later this week, and Coveney praised the good cooperation between Barnier's task force and Dublin.

"So far we have really been in unison," he said.

Good Friday agreement

Coveney said there has been good progress made between UK and EU negotiators last week on the common travel area, which allows UK and Irish citizens to travel without passport checks across the border.

But he added that there is a "lot more work" that needs to be done to make sure that the Good Friday agreement, the 1998 peace accord, is not endangered by Brexit.

"There is an obligation to achieve more progress to reassure people that it [Brexit] won't have damaging effect on the peace process," Coveney said, admitting that the complete solution and the final, new relationship between the UK and Ireland will not be known in detail until the future trading relationship is fully negotiated.

He echoed what EU officials have been saying, that unless there is progress on the issue of financial settlement between the UK and the EU, those second phase negotiations on the the UK's future relationship with the bloc cannot begin.

"There is a very strongly held view that more progress needs to be made and can be made on the financial issue and Ireland," he said.