The SDLP and Sinn Fein have clashed over allegations that the Minister of Agriculture, Ms Brid Rodgers, is being intimidated by republicans.
Sinn Fein yesterday rejected suggestions that it was behind attempts to intimidate SDLP canvassers in the West Tyrone constituency.
Ms Rodgers, who is vying with Sinn Fein vice-president Mr Pat Doherty to unseat the current MP, Ulster Unionist Mr William Thompson, complained of being verbally abused twice while campaigning over the past few days. The latest incident happened on Sunday in Omagh, Co Tyrone, and follows an earlier one on Thursday in the town of Greencastle, according to her election agent, Mr Joe Byrne. "People can draw their own conclusions as to who is behind these incidents, which include the systematic taking down of posters, following canvassers, telling our people not to put up billboards, and verbally abusing the candidate herself," he said.
An SDLP election worker who was putting up posters in Carrickmore, Co Tyrone, on Wednesday said he was told his van would be burnt if he did not leave the area immediately.
Sinn Fein six-county chairman Mr Fra McCann rejected any suggestion that Sinn Fein had been involved in disrupting or threatening the SDLP.
"This is a disgraceful accusation and I demand the SDLP withdraw it immediately," he said.
Mr McCann accused the SDLP of "running scared and resorting to smear tactics" in their efforts to win West Tyrone.
Mr McCann said that Sinn Fein party workers had also been the targets of intimidation.
"In recent weeks our election workers have been attacked by loyalists and the RUC. Posters have been pulled down and cars have been attacked," he said.
A car belonging to Mr Thomas Guiney, a Sinn Fein election worker in Ballycastle, Co Antrim, was set alight and destroyed outside his home on Saturday night.
The SDLP's north Antrim candidate, Mr Sean Farren, condemned the attack.
"Attacks on election workers of whatever party strike at the heart of democracy. Such attacks display fascist attitudes," he said.
Both the SDLP and Sinn Fein have predicted that they will win the West Tyrone seat.
Mrs Rodgers said independent opinion polls consistently put the SDLP ahead.
"This has been corroborated by our own canvass returns, which are showing growing support for the party and our candidates in West Tyrone and Fermanagh/South Tyrone. There is a recognition that this election matters," she said.
Mr Doherty, however, said Sinn Fein was on target to "win the west".
"People in Fermanagh/South Tyrone and people in West Tyrone are sick of years of unionist misrepresentation and are poised to repeat the performance of Martin McGuinness in Mid-Ulster at the last Westminster election by electing Sinn Fein MPs," he said.