Images circulating online show a ‘stop the boats’ placard on the pyre at Cornagrade Road, Enniskillen.
The PSNI said it was aware of the matter.
Jemma Dolan, a Sinn Fein MLA for Fermanagh-South Tyrone, branded it racist.
“Halloween is meant to be a fun and welcoming event for everyone in our community and to see this sign draped across a bonfire in Enniskillen is unacceptable and wrong,” she said.
“Illegal bonfires put lives at risk and at times are being used to spread hate.
“It is the responsibility of political representatives to show leadership. We need to tackle illegal, unregulated and dangerous bonfires.”
A PSNI spokesperson said: “Police are aware of signage placed on a bonfire in the Cornagrade Road area of Enniskillen. Enquiries into the matter are on-going.”
In July, there was outrage after an effigy of refugees in a boat was placed on an Eleventh Night bonfire in Moygashel, Co Tyrone.
The model of a small boat with several figures inside was accompanied by a banner saying “stop the boats” and “veterans before refugees”.
At the time, Moygashel Bonfire Committee said it was intended to express “our disgust at the ongoing crisis that is illegal immigration”.
Meanwhile, firefighters in Northern Ireland had a slightly less busy Halloween than last year, according to the number of callouts.
The Northern Ireland Fire and Rescue Service (NIFRS) said from 6pm on October 31 to 1am on November 1, its crews responded to 53 operational incidents.
A spokesperson said that several of the incidents were Halloween-related, including bonfires and fireworks.
The PSNI are investigating the sign on the bonfire. Photo: X
News Catch Up – Friday 31 October
The figure represents a drop on the previous year, when between 6pm on October 31, 2024 and 1am on November 1, 2024, fire crew responded to 63 operational incidents.
Then, a NIFRS spokesperson described several of the incident as being Halloween-related, including 16 bonfires.