An Irish senator has called the planned proposal for the border of Northern Ireland a mock-up of a "smuggler's charter."
Prime Minister Theresa May has assured Irish nationalists the UK does not want to see borders imposed along the border to the Republic of Ireland from the north.
The 300-mile border is the UK's only land connection with an EU country.
Mark Daly, the deputy leader of Fianna Fail, said the plans to maintain the border looked like "fiction and clueless [sic]."
He told Julia Hartley-Brewer: "The British Government are throwing out lines like 'frictionless and seamless border' hoping it’ll gain traction with the EU.
"But hope is not a policy. The reports and proposal coming out about a 'frictionless and seamless border' look like fiction and clueless.
"On this island, the proposal they’ve put forward to the EU is in reality a smuggler's charter."