London may never come up with a credible proposal on Brexit, according to the Fianna Fáil leader.
Earlier President of the European Commission, Jean-Claude Juncker, addressed the Dáil ahead of next week's EU Council meeting.
He said there can only be a deal that ensures no return to a hard border with Northern Ireland.
Fianna Fáil leader Micheál Martin has not been impressed by proposals from the British government.
"There comes a point where we will have to stop shaking our heads at the undoubted incompetence and incoherence of London's position," said Mr Martin.
"The exotic edges of the Tory party have long since stopped being amusing, no matter how absurd their cast of characters is.
"The simple fact today is, that London may never come up with a credible proposal."
Meanwhile, Mary Lou McDonald accused the British Government of having a policy of 'Ireland last' when it comes to Brexit.
The Sinn Féin leader says Theresa May is using delaying tactics to put off dealing with the question of the border with Northern Ireland.
"I met with the British Prime Minister yesterday and she sets out a policy of Ireland last - if at all," said the Dublin Central TD.
"It seems to me now clear that British policy and tactics is to run down the clock. To delay and delay again."
- Digital Desk