Loyalists have erected a banner on the Shankill Road attacking Sinn Féin Lord Mayor John Finucane.
The banner targeting the party's Westminster candidate appeared on the wall of an apartment block on the Lower Shankill early on Monday morning.
Mr Finucane's father, human rights lawyer Pat Finucane was murdered by a Shankill based UDA gang in 1989.
The poster, which features a picture of IRA bomber Sean Kelly, who in the past has canvassed for Sinn Féin in North Belfast, is being linked to a wider campaign by loyalists across Northern Ireland.
Banners stating 'Ulster Says No - to an economic United Ireland' have been appearing in towns and villages across the north in response to Boris Johnson's withdrawal agreement that proposes regulatory arrangements including a sea border.
Loyalists have also held a number of town hall style meetings, from which the media have been mainly excluded. The well attended meetings have included senior figures from various loyalist paramilitary factions.
The controversial banner, targeting Belfast's first citizen, who is challenging incumbent DUP MP Nigel Dodds for the north Belfast seat, is thought to be linked to the loyalist campaign.
Last week police were alerted to threats to members of UUP staff in north Belfast after the party's new leader Steve Aiken said he would stand candidates in all 18 seats.
The UUP later announced it would not be fielding a candidate in the constituency.
A loyalist source told the Irish News that the aggressive campaign against the Sinn Féin candidate would continue to keep the Westminster seat "in unionist hands".
Sinn Féin declined to comment on the development but it is believed legal action to force the property owner to remove the banner is being considered.
