Sinn Féin leader Mary Lou McDonald has told party members that the time has come to have the discussion on Irish unity.
Speaking at an event in Belfast, Ms McDonald said a growing number of people in Nothern Ireland, including many from a unionist background, are now considering their future in the context of Brexit.
She said many are now open to discussing the prospect of a new Ireland, an agreed Ireland and a united Ireland.
Ms McDonald said it was a "choice between the narrow negative self-serving divisive decisions taken by little Englanders in Westminster or a shared, inclusive future in which we take decisions together in the interests of the people of this island".
Ms McDonald also kept alive the possibility of Sinn Féin reaching an agreement with the DUP and other Stormont parties on the restoration of power-sharing.
She said: "The negotiators have met; the various parties' positions are well rehearsed, now is the time for resolution."
Ms McDonald confirmed that Sinn Féin and other Stormont parties are expected to meet British Prime Minister Boris Johnson in Belfast tomorrow.
During her address, she accused Mr Johnson of trying to bully the European Union and Ireland and said the Withdrawal Agreement is not up for negotiation and the backstop was the bare minimum required to safeguard Irish interests.