DUP leader Arlene Foster has warned voters that a poor performance by the DUP in this month's European elections will be interpreted in London and Brussels as a vote for no Brexit.
Backing DUP candidate Diane Dodds, Mrs Foster added that she was opposed to a confirmatory Brexit referendum as it 'would place democracy at risk'.
"I am opposed to a second referendum but weak DUP vote will be interpreted in London and Brussels as a vote for no Brexit," she said
Mrs Foster, who was attending the launch of her party's European election manifesto in Belfast, also criticised Prime Minister Theresa May for lacking the vision of a strong United Kingdom post-Brexit.
"What people want to see is democracy being respected. Unfortunately it hasn't been respected and we have a Remain parliament, therefore parliament has not been able to deliver on Brexit in the way it should have been delivered upon," she said.
"We have a Prime Minister frankly who doesn't have the vision for the United Kingdom post Brexit that we all want to see. We want to see a United Kingdom that is strong post-Brexit and has a close relationship with Europe."
The DUP and Sinn Fein are heavily tipped to retain two of Northern Ireland's three European seats. The fate of the third seat, held by the retiring Ulster Unionist Jim Nicholson, is less certain.
The vote in Northern Ireland is conducted on the single transferable vote system.
Mrs Foster urged supporters to vote DUP as their first preference and then back fellow unionist candidates down the ballot paper.
"We will be urging people to seize this moment," she said.
"As we travel the laneways and villages of Ulster we will be telling every door, don't let Michel Barnier or Jean Claude Junker misrepresent your vote.
"It's time to tell them again. It's time to Vote Dodds 1 and defend the Union and deliver Brexit."
Mrs Foster said that London and Brussels needed to know that implementing the referendum result need not be a choice between respecting the result and the Union. "We must all leave on the same terms," she said.
"It was a United Kingdom decision and we will continue to reject any trade barrier between Northern Ireland and the rest of the United Kingdom.
"Whilst some unionists will have voted 'remain' in 2016, I have spoken with dozens who now recognise that whatever their preference, the democratic wishes of the people must be implemented."
Mrs Dodds accused the EU of treating the UK with contempt.
"In June 2016, almost 350,000 people in Northern Ireland voted to leave the European Union as part of the UK wide vote," she said. "It's time to deliver Brexit and respect democracy.
"We must fight this election and secure a mandate which is heard loudly in Brussels and London. The stakes could not be higher. The health of our democracy is on trial. In 2016 people voted in good faith that their will would be implemented.
"They must be able to have faith that the biggest democratic decision in our lifetime will be respected.
"After almost three years of hopeless government negotiation and utter contempt and intransigence by Brussels, the referendum result still hasn't been implemented. That simply isn't acceptable.
"This election is an opportunity to send a message to London and Brussels that the vote to leave the EU must be respected."
Mrs Dodds said she had a message to those who highlight that Northern Ireland voted to Remain (56%).
"The 2016 referendum was not an English vote, a Scottish vote, a Welsh vote or a Northern Ireland vote," she said. "It was a British vote - a national vote - to leave the EU together and it must be honoured."
