A vote for Sinn Féin in next month's Westminster election will strengthen the argument for a border poll, the party's manifesto claims.
Sinn Féin is seeking a referendum on Irish unity within the next five years – a timescale that was absent from the party's manifesto for March's assembly election.
In the shorter term, republicans want special designated status for the north, preserving access to the single market and customs union.
The party is also seeking an end to the Conservative government's cuts to public services while securing an Irish language act and marriage rights for same-sex couples.
The policy blueprint also makes a pledge to maintain access for farmers to the EU Common Agricultural Policy subsidies.
The bi-lingual manifesto was launched at Dungannon's Junction in the Fermanagh-South Tyrone constituency, where former Stormont agriculture minister Michelle Gildernew is seeking to win back the seat from the Ulster Unionists. Elsewhere, the party is defending four Westminster seats.
Sinn Féin northern leader Michelle O'Neill said the importance of June 8's election could not be overstated.
"The political stakes are very high," she said. "This is probably the most important election of a lifetime."
The Mid Ulster MLA said March's Stormont election had shown that people wanted government based on equal partnership between unionists and nationalists.
She said the electorate's message had "either not registered or is being ignored by senior DUP public representatives".
"There is no doubt that this will be a ground-breaking election for Sinn Féin – Irish unity is now firmly on the agenda," she said.
Ms O’Neill repeated her party's commitment to restoring devolution but said the talks process had been held up by the Tories' "narrow self-interest".
"We want the executive to work but it has to be a good executive," she said.
She said next month's poll was "no Brexit, no border, no Tory cuts".
"We have to fight back against the reckless and dangerous policies of the self-serving Tory government in London, which is about forcing a disastrous Brexit on the North and dragging us against our will from the EU," the Sinn Féin northern leader said.
"Everyone here knows the impact that will have on our business, trade, agri-food, tourism and other sectors of the economy, with the imposition of trade tariffs, a border and denying people the freedom of movement North and South. It will severely undermine the progress of the past 20 years."
Ms O’Neill said that people would “not tolerate inequality and discrimination or second class citizenship for anyone – women, LGBT, Irish speakers, ethnic minorities – because an attack on one, is an attack on us all.
On a border poll, the manifesto says there should be a 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," it states.
"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.
Mrs O'Neill said her party were "proud abstentionist" and that she believes "other nationalists should do the same".
She claimed the SDLP had been ineffective at Westminster and had failed to stop Brexit, the triggering of article 50 and Tory cuts."
