DUP leader Jeffrey Donaldson has said the forthcoming Stormont Assembly election is a battle for Northern Ireland itself.
In an Easter message to party colleagues, he has again claimed that a Sinn Féin victory in the poll would help it deliver on its objective for a referendum on Irish unity.
Sinn Féin has said that its focus in the election is on pressing health and economic issues in Northern Ireland, such as the cost-of-living crisis and spiralling hospital waiting lists.
Mr Donaldson has, however, maintained that the republican party will be emboldened to press for a referendum if it displaces the DUP as the largest party following the election on 5 May.
Unionist rivals have accused him of trying to scare the unionist electorate into voting DUP to consolidate his party's support in the wake of a series of opinion polls that have indicated it is trailing behind Sinn Féin.
In his message to DUP members, Mr Donaldson claimed the election will "set the direction of the country for the next decade".
He wrote: "This election is the most important for a generation.
"Voters have a clear choice between our plan for fixing health, helping working families with the cost-of-living crisis, and growing our economy within the Union, and Sinn Féin's divisive border poll plan.
"The election outcome will decide if Northern Ireland goes in the right direction or the wrong direction.
"Over the last week, I have been focusing on constituencies where unionism is only chasing one seat.
"I have been reminding the people in those areas that voting for parties that can't win will risk the seat. Despite what some people say, you can split the vote too thinly in a PR election.
"I am also reminding them that this is a battle for Northern Ireland."
Mr Donaldson continued: "The DUP is the only party that can stop Sinn Féin's divisive border poll plans. A first preference vote for any party other than the DUP will divide and weaken the unionist cause and help Sinn Féin win and deliver on their border poll plan.
"Make no mistake, if Sinn Féin win this election, their plan for a divisive border poll will be advanced.
"If Mary Lou McDonald and Michelle O'Neill win, the whooping and cheering count centre speeches will not be about the National Health Service.
"They will not be about advancing 30 hours free childcare for families.
"They will not be about removing the Irish Sea border.
"They will be about a divisive border poll.
"The DUP has a Five Point Plan for Northern Ireland which is focused on the issues that matter to everyone but Sinn Féin's only plan for Northern Ireland is a divisive border poll."