The City of Fremantle is warning police about hoax fliers which appear to have been distributed ahead of broadcaster and Fairfax columnist Waleed Aly's appearance at the Fremantle Festival on Saturday.

Fremantle Mayor Brad Pettit told WAtoday he had seen an electronic version of the flier which labels Aly a "child molester".

Waleed Aly is the co-host of Channel Ten's The Project.

"I first heard about this on Friday and we have let the police know about it. The event will go ahead as planned," he said.

The co-host of Channel Ten's The Project is due to make the keynote address at the Fremantle Festival on Saturday afternoon.