Ms Hanna, outlining the SDLP's opposition to the European Union (Withdrawal Agreement) Bill, said: "For Northern Ireland in particular, Brexit has sharpened all of the lines that the Good Friday Agreement was designed to soften around identity, around borders, around sovereignty.
"We should have been spending the last few years talking about reconciliation, talking about regeneration, talking about social justice and equality.
"That's what all political action should really be about but instead we've spent morning, noon and night talking about Brexit - a problem that didn't need to exist and which, particularly in Northern Ireland, reopens old wounds and limits our horizons."
Ms Hanna said Brexit "fed off" people who felt lost and disenfranchised in the political system, adding: "I fear it will leave them feeling much worse."
She also said: "Beyond the economy, Brexit upends the delicate balance that in Northern Ireland has allowed us to imagine our shared and equal future together.
"We in Northern Ireland know the value of the EU and, as my political hero and predecessor in this House John Hume so often said, the EU is the greatest peace-building and conflict resolution project anywhere in the world and those of us particularly affected by conflict have a duty to reflect its principles.
"I'm afraid the concerns we have have been dismissed by those of you who won't ever have to live with the consequences of these actions."