A full inquiry into the ongoing robocall scandal must be held in order to assure the public doesn't lose faith in its government, says a longtime NDP MP.

Olivia Chow made the comments during a rally at Yonge-Dundas Square Sunday afternoon.

The rally, attended by about 500 people, was one of dozens taking place across Canada in what was billed by organizers as a "day of action against electoral fraud".

Elections Canada is reviewing more than 31,000 reports of Canadians receiving misleading calls about where to vote during May's federal election.

About 42,000 people have signed an online petition for a public inquiry into the matter.

"Stephen Harper must respect democracy. He cannot be soft on crime and this is a crime," Chow told CP24. "We have to respect democracy because our forefathers died fighting for it."

After congregating in Yonge-Dundas Square around 2:30 p.m. the protesters, many of whom armed with placards and megaphones, marched to Old City Hall.

Though there was heavy police presence, including some officers dressed in riot gear, the protest was peaceful.

"This isn't just a simple dirty trick or a smear campaign; it is an attack on our right to vote in this city," organizer Derek Soberal told CP24. "Canadians are engaged and they are concerned. We need to have a full criminal investigation to restore our faith in the voting system."