The SDLP has accused Sinn Fein of harassing some of its election workers campaigning for their candidate Brid Rodgers.
They have said posters have been ripped down and verbal abuse has been directed at canvassers.
Sinn Fein have denied the claims and have accused the SDLP of running scared because they think they are losing to the republican candidate Pat Doherty.
The seat is being fiercely contested by both parties.
It has a natural nationalist majority but this vote will be split which could allow it to stay unionist as happened at the last election.
Willie Thompson who has held the seat for the Ulster Unionists is the third contender in the field.
Meanwhile a Sinn Fein election worker's car has been destroyed in an arson attack in Ballycastle, County Antrim.
It happened at Marconi Park at 0500 BST on Sunday morning.
It is understood the man was recently threatened by the paramilitary Loyalist Volunteer Force.
The RUC have said they are also examining the contents of a letter which was put through his letterbox on Sunday morning.
The hardline LVF split from the mainstream loyalist paramilitary group the UVF and carried out a series of sectarian murders during the 1998 all-party Good Friday Agreement talks.