Sinn Fein has called for an Irish unity referendum within five years.
The republican party said ending partition of the island between Northern Ireland and the Republic had gained a new urgency following the Brexit vote.
The party added the north should enjoy designated special status within the EU after the UK exit.
The remaining 27 member states have declared that Northern Ireland can resume membership if the island is united.
Sinn Fein leader Michelle O'Neill predicted another "groundbreaking" poll on General Election day on June 8.
The manifesto said: "Sinn Fein believes there should be a referendum vote on Irish unity within the next five years.
"The imposition of Brexit and cuts from the Tories demonstrates the unjust and undemocratic nature of partition and the union.
"Ending partition has now taken on a new dynamic following the Brexit referendum."
The party said the EU had shown itself flexible in handling different forms of integration and relationships for member and non-member states.
It added: "Designated special status would preserve access to the single market and customs union, ensure that we retain the Common Travel Area and maintain access to all EU funding streams."
The electoral blueprint promoted a message of anti-austerity, integrity and respect.
It supported frontline health service staff, a secure education system, an all-Ireland charter for fundamental rights and help for farmers.
Northern Ireland voted to remain in the EU by a majority of 56% to 44%, although large swathes of unionist territory opted to leave.
Mrs O'Neill said Northern Ireland was being treated as collateral damage by the Tories and dubbed it the most important election of a lifetime.
The party is defending four seats and hopes to win more.
She added: "This is going to be another momentous election."
Sinn Fein abstains from taking its Westminster seats and has been heavily criticised by rival nationalists the SDLP.
Mrs O'Neill added: "We are proud abstentionists and we think other nationalists should do the same."
She said the SDLP had not been effective at Westminster.
"They have not stopped Brexit, they have not stopped the triggering of Article 50, they have not stopped Tory cuts."
The leader said Sinn Fein wanted to be in powersharing devolved government at Stormont as a bulwark against Tory cuts.
The administration collapsed earlier this year.