The DUP has been accused of labelling anyone who supports the people of Palestine as republicans.
Gerry Carroll, who was elected to the city's first super-council, was speaking after around 1,000 people gathered in Belfast in a show of solidarity with the people of Palestine.
The People Before Profit politician said the demonstration through Belfast on Saturday included people from many religious backgrounds.
Mr Carroll said: "There's been a conscious attempt to divide those who support Gaza by the DUP. But we want to make it clear that there are people from all different types of background who attend these marches, whether they are Catholic, Protestant, migrants or Islamic, and that's reflected in the crowd.
"The DUP are trying to paint it that anyone who supports Palestine is republican and that makes it difficult for anyone who doesn't have a political affiliation here and are just concerned about Palestine. They are pushing people away from Palestine and in effect supporting Israel."
In response, Belfast DUP councillor Tom Haire claimed that people who attend Gaza marches tended to come from nationalist areas. "To a certain point that appears to be true and I think there's a certain merit in what he [Mr Carroll] says," he added.
"If you look at where the protests and boycotts have taken place they are all in nationalist areas. I certainly would not be taking part in any such march that he organises."