Sinn Fein leader Mary Lou McDonald has condemned any potential return of violence on the island of Ireland.

Ms McDonald said a new reality had emerged on the island that there was no appetite for violence of any kind.

“There is no circumstances, no excuse, no scenario in which anybody from any disposition anywhere across this island would have a justifiable cause to take up arms,” she said.

“There is no appetite for a return to armed actions anywhere across this island, in any community in the north of Ireland and, in fact, people have embraced a new reality right across our country which is one of relative stability and advancement and progress.”

Ms McDonald made the comments at Leinster House on Tuesday amid ongoing Brexit chaos and after a parcel bomb was found last week at an Irish postal depot, which appeared to be identical to suspect packages found in the UK earlier this month.

Army bomb disposal experts were called to a postal sorting office in Limerick on Friday morning after the suspicious package was discovered.

The Irish Defence Forces later confirmed a viable improvised explosive device had been found contained in a plastic envelope.

Ms McDonald accused Irish premier Leo Varadkar of being overly relaxed when it came to no-deal planning.

“We heard An Taoiseach in the course of the weekend almost philosophically say that whereas Brexit might define Britain for a generation, that it doesn’t have to define us,” she said.

“I think it’s a very worrying statement. I think it belies an overly relaxed attitude by An Taoiseach.”

The Dublin Central TD described the DUP’s approach to Brexit as “absolutely reckless and dangerous”, adding it was entirely at odds with what was best for everybody in Northern Ireland.

“You can’t have part of the island inside the European Union and the other part outside of the European Union, and imagine that there won’t be huge consequences for trade and our economy but also, critically, for the enjoyment of rights by our citizens and for the smooth operation of the Good Friday Agreement,” she said.

Ms McDonald continued: “They are very much out of step with public opinion in the north. I think they’re very well aware of that and yet they are quite content to play very, very dangerous games with their friends in the Tory party.”

Other members of the opposition also voiced their concern over the lack of information being provided by the Government about what will happen to the border in a no-deal scenario.

Fianna Fail Brexit spokeswoman Lisa Chambers said the Government needed to explain what discussions were happening at EU level.

“It’s about time now our Government was honest with people because clearly conversations are happening in the background,” she said.

“We’re getting little snippets. We’re piecing together little snippets from EU officials from various ministers… but that information should be forthcoming.”

Irish Labour Party leader Brendan Howlin said it was a very worrying time for Ireland as the “Brexit shambles continued apace”.

“It’s incumbent on our government to prepare unfortunately for a hard Brexit,” he said.

“Very inadequate preparation has been explained to us to date.”

Mr Howlin called on his British counterparts to back Theresa May’s deal.

“If the choice is a no-deal or the deal that’s on the table, I would exhort the British Labour Party to support the only negotiated deal that’s there,” he said.

But he added the ideal outcome would be if Article 50 was revoked entirely or Britain had a second referendum.