Taoiseach Enda Kenny has raised the possibility that British Prime Minister Theresa May could trigger plans for the UK to leave the European Union before the March 2017 deadline she has already fixed.

At a seminar in Dublin, Mr Kenny indicated there is scope for the process to begin earlier.

In unscripted remarks at the close of this morning's session, Mr Kenny said while the end of March is the deadline for Ms May to trigger Article 50, the formal process could begin in December or January.

He said he will keep other political parties fully briefed at the different stages of negotiations.

Political leaders from both sides of the border stated that the island of Ireland will be the EU region most affected by Brexit.

Mr Kenny also said that people will continue to be able to travel freely between Ireland and the UK, post-Brexit and has agreed with Ms May that the "benefits of the Common Travel Area" between both countries are preserved.

Addressing the All-Island Civic Dialogue, a cross-border gathering of politicians, business leaders, community representatives and others, Mr Kenny said he "acknowledges" that Northern Ireland voted to remain in the EU in June's referendum.

Mr Kenny also pointed out that access to the European Union Single Market requires the acceptance of the freedom of movement of people.

The Taoiseach said Northern Ireland and the peace process would be front and centre of Dublin's priorities in the upcoming negotiations between Britain and the remaining 27 EU leaders over the terms of Brexit.

Mr Kenny said the event was "a response to the unique situation that has been created on this island by the UK's vote to leave the European Union".

He continued: "Brexit is an issue that has the potential to impact everybody on this island - north and south.

"It has implications for so many aspects of our relationship. It presents the most significant economic and social challenge of the past 50 years."

Northern Ireland's two main unionist parties are not attending. But leaders of the island's other main parties and groupings will have an opportunity to speak.

Ibec's northern equivalent, the Confederation of British Industry, and the Ulster Farmers' Union as well as several Northern Ireland local authorities and other organisations sent delegates.

Fianna Fáil leader Micheal Martin criticised UK ministers for pushing a "crude and chaotic" Brexit agenda.

Urging Ireland to attempt to soften the UK's exit from the EU, he said June's "divisive and damaging" referendum result had profound short, medium and long-term implications for Ireland.

"Our agenda is the clear one of wanting to minimise the damage and division of Brexit and to maximise progress for all parts of this island," he told the forum.

"Let's explore radical ways of softening Brexit, but we also have to talk about the crude and chaotic Brexit which some in the London cabinet appear to be advocating.

"Unlike the Foreign Secretary (Boris Johnston), we don't have the luxury of being pro-having the cake and eating it."

Sinn Féin leader Gerry Adams said the forum should "not be about a hard Brexit or a soft Brexit. It needs to be about moving beyond the consequences of Brexit and looking at alternatives".

He said his party wanted a referendum on Irish unity, but also suggested a "designated special status" for Northern Ireland, citing other unique EU arrangements like Denmark/Greenland.

"That threatens no-one's constitutional preference and this State, as a continuing member of the EU, has the right, and in our view the obligation, to bring forward such a proposal," he said.

"The EU has proved itself capable of accommodating unique circumstances."

Labour leader Brendan Howlin said further discussions should be planned to devise an agreed strategy for negotiations at EU level, while Green Party leader Eamon Ryan said he would like the referendum to be run again in the hope that it would produce a different result.

Newly-elected leader of Northern Ireland's Alliance Party Naomi Long said she welcomed the opportunity to participate in the event.

In a reference to calls by Sinn Féin and others for a border poll, she said she favours decoupling the Brexit debate from such argument.

The organisers of today's event say the intention is to use it to discuss the consequences, possible opportunities as well as the problems that may arise from the UK decision.

Meanwhile, Minister for Jobs, Enterprise and Innovation Mary Mitchell O'Connor is in London for talks with her UK counterparts on the impact of Brexit and Trade and Single Market issues.

She said: "It is crucial that the UK cabinet fully appreciate the potential impacts for Ireland and especially North/South economic relations, before any detailed negotiation process commences". 

The High Court in London will tomorrow deliver its verdict on whether British politicians, rather than the government, must trigger the formal process of leaving the EU.