The SDLP has claimed that ‘vote stealing’ occurred in Foyle during the general election.
Mark H Durkan, nephew of Mark Durkan who lost his seat by 169 votes to Sinn Fein's Elisha McCallion, met the chief executive of the electoral commission this morning to present evidence of the alleged fraud.
Mr Durkan told the Irish News: "Prior to the election I had expressed concerns to the electoral office and to the PSNI regarding breaches of the electoral rules constituents had raised with me.
“While the PSNI have stated publically that they are investigating the concerns that have been reported to them, since the election, more constituents have approached me about their votes being stolen on polling day.
“Today, I am meeting with the chief executive of the electoral office to present the evidence and to ask for an investigation.
“This is a matter of public confidence and it is critical that all efforts are made to ensure that any malpractice is not tolerated.”
The loss of Foyle was a huge and unexpected blow for the SDLP which had coveted the seat since their party founder John Hume was elected in 1983.
Vote stealing is when people visit their assigned polling stations only to be told that their vote had already been cast. There have been reports of vote stealing in Derry from Good Shepherd Primary School, Holy Family School and Lenamore Primary School.
A PSNI spokesperson said that they are investigating a small number of reports of electoral fraud, following a referral from the electoral office, and that enquiries are ongoing.
Chief Superintendent Karen Baxter said: "We work closely with the electoral office and where information becomes available in relation to criminal activity, we take action."
Mark H Durkan claimed that on polling day and in the days following he and a number of others were contacted by people who said that when they went to vote they were told they had already voted.
He said: "It's difficult to gauge how widespread it may be. Part of my meeting with the Electoral Office is to try and establish how many people this did happen to.
"It is vitally important to all parties that we have an electoral system that people can have faith and confidence in.
"We need to know what steps are going to be taken to eradicate these type of incidents in the future."
In South Down, SDLP MLA Colin McGrath said he had been made aware of "at least a dozen" similar incidents.
"We can't say at this stage if votes had been stolen or anything like that but it is very strange," he said.
"We need to find out how many times this happened and I will be meeting with the Electoral Office to try and determine exactly what happened."
Nobody from the Electoral Office was available to comment.