He made the comment during a conversation with former IRA hunger striker and Sinn Fein MLA Raymond McCartney, as part of a community festival in Londonderry.
Mr Corbyn also suggested Brexit has led to the “the island of Ireland as a whole” becoming a “stronger, self-looking economic entity”.
He said: “In a way the issues of the debate over Brexit have meant that the island of Ireland as a whole has become a stronger, self-looking economic entity than it was before and I think that’s quite significant and it’s quite important.”
But DUP MP Gregory Campbell hit back, saying in a statement issued to the News Letter: “Jeremy Corbyn’s Labour Party became synonymous with anti-Semitism.
“He has been unable to forthrightly condemn terrorism and he snubbed innocent victims on his last visit to Londonderry despite my repeated invitations to him. Instead of any focus on those issues, the ‘interviewer’ desperately probed for a few crowd-pleasing comments about a united Ireland.”
He added: “It is not Brexit which has caused the damage to Northern Ireland’s economic and constitutional position but the Northern Ireland Protocol which Jeremy Corbyn also voted against.
“It isn’t the views of someone who failed to become prime minister which matter however, but the actions of the current prime minister. The government white paper was a step forward, but must be matched by actions to remove the Irish Sea border.”
Mr Corbyn, who has been a long-term supporter of a united Ireland, also said during his talk at the Féíle event that he was watching the debate around partition and the potential for reunification “very closely indeed”.
Asked whether now is the right time to “examine partition” during his conversation with Mr McCartney, he said: “It is the time to examine partition and the 100th anniversary of it is a great time to do that, to understand the historical process that led to it and understand the political opportunities that encouraged it at that time – and the price of it.”
At other times in the conversation, Mr Corbyn discussed his fascination with the “brutality of the treatment of the Irish people going back to the English occupation, going back to Cromwell and what he did at the end of the English civil war when he tried to march those who fought against the English crown in order to establish a colony in Ireland, so he was practising his own imperialism.”
Mr Corbyn has consistently supported a united Ireland.
In a 2015 interview with the New Statesman magazine he said “it’s an aspiration that I have always gone along with”.
In 2018 he said he would not advocate for a poll on whether Northern Ireland should leave the UK, but said it “would be a decision that could be made within the terms of the Good Friday agreement”.