SDLP leader Mark Durkan has said the party never had any "gentleman's agreement" to stand aside in West Tyrone in the general election.
Mark Durkan says SDLP never agreed to stand aside in West Tyrone
The party has been embroiled in an internal disagreement about whether it should stand against hospital campaigner Dr Kieran Deeny.
The SDLP has selected assembly member Eugene McMenamin to contest the seat.
Mr Durkan said his party had released two letters from Dr Deeny to prove the SDLP had never agreed to stand aside.
Speaking on BBC Radio Ulster on Friday, Mr Durkan said: "Kieran Deeny hadn't even met me, or had a conversation with me."
He denied the SDLP had released the correspondence in order to damage Dr Deeny's campaign.
"If we were out simply to damage Kieran Deeny we would have released far more of his letters," Mr Durkan said.
He said proposals from Dr Deeny suggested other parties, not just the SDLP, would stand aside in West Tyrone.
"It became clear to people that the proposals Kieran Deeny was putting forward didn't stand up," the SDLP leader said.
On Thursday, Dr Deeny said he was standing by correspondence with the SDLP which suggested that one day he could be a candidate for the party.
The emails could cause problems for Dr Deeny gaining cross-community support.
They contain speculation by Dr Deeny about his future direction in mainstream political life.
"Once I do actually get involved in functioning politics, I may see quite quickly that in Northern Ireland it would be much better to be part of a bigger party to be able to achieve services for people," it says.
"So who knows, I could be an SDLP candidate for the next assembly election (whenever that takes place) and that, of course, also could mean the becoming of an SDLP MP."
Mr Deeny denied his comments were an offer to join the party.
He told the Press Association: "What I was saying in the email was who knows what might happen in politics?
"My politics have always been social democrat. My father was an SDLP supporter and I was brought up in an SDLP town.
"I would be inclined towards any party which is cross-community and social democrat in its principles."
Dr Kieran Deeny won an assembly seat in 2003
Dr Deeny topped the poll in the Northern Ireland Assembly election of November 2003.
He had a surprise victory when he won a seat on a single issue ticket to save hospital services in Omagh.
In February 2004, he talked about setting up his own party.
"If I simply am seen as a protest vote, I will get nowhere," he said at that time.
The West Tyrone seat is also being contested by the DUP's Tom Buchanan and the Ulster Unionist's Derek Hussey.