Sinn Féin today challenged the SDLP to say whether it would back a post-election referendum on Irish unity.
Sinn Féin general secretary Mitchel McLaughlin - in a fierce battle with the SDLP leader Mark Durkan for the Foyle House of Commons seat - called on his rivals to demonstrate their support for a united Ireland by demanding a Border poll.
Mr McLaughlin said: "Given our two parties espoused position in favour of Irish unity, I would expect that the SDLP would back an immediate call for a referendum on partition.
"After the elections are over, we intend to engage the SDLP on how we can best prosecute the united Ireland agenda with the parties and the two governments.
"Both parties - Sinn Féin and the SDLP - are saying the same thing: we wish for a united Ireland. Both parties should therefore push for a referendum on the Border immediately following the elections," he said.
Both parties have both released strategy documents for achieving a united Ireland.
The SDLP argued it would preserve the Stormont Assembly and Executive set up under the Good Friday Agreement in a united Ireland as well as the accord's equality and human rights protections including a Bill of Rights.
The party's document also insisted a referendum should be held once the Good Friday Agreement institutions were bedded down and stable.
Sinn Féin's discussion paper calls on the Government to draw up a strategy towards Irish unity, with a Green paper completed within one year identifying steps and measures that can assist and promote the successful transition to a united Ireland.
The Government, the party believes, should negotiate the issue with the British government and support should also be sought internationally.
PA